EXOSKELETON FOR ASSISTING HUMAN MOVEMENT

Abstract

The invention relates to an exoskeleton for assisting human movement, which can be fitted to the user in terms of dimensions, tension and ranges of joint motion, either manually or automatically. Said exoskeleton can be fitted to the user in the anteroposterior direction in the sagittal plane, with the user in a horizontal or sitting position, without requiring a functional transfer. The exoskeleton has a modular design which is compatible with human biomechanics and reproduces a natural and physiological movement in the user, with up to 7 actuated and controlled degrees of movement per limb, ensuring that the user maintains equilibrium during locomotion.

Claims

1-26. (canceled)

27. An exoskeleton for assisting human movement that comprises a mechanical structure, wherein the mechanical structure comprises segments joined by joints that enable the relative movement between two or more successive segments for moving the limbs (10) of the user lending them a natural gait and a fastening system (2) that allows it to carry out its coupling to the human body characterized in that the fastening system (2) comprises a rigid lumbar reinforcement (20) that in turn comprises two or more segments that can be coupled (21), two of which are joined to the segments of the exoskeleton by means of at least one rotation shaft (22), wherein the lumbar reinforcement is retractable by means of successive rotations until it is located in the sagittal plane.

28. The exoskeleton for assisting human movement according to claim 27 comprising at least 6 degrees of movement in each lower limb, these degrees of movement being the following; flexion and extension of the hip (31) by means of rotation in the sagittal plane; abduction-adduction of the hip (32) by means of rotation in the lateral plane, rotation of the hip (33) by means of rotation in the transverse plane; flexion and extension of the knee (34) by means of rotation in the sagittal plane; flexion and extension of the ankle (35) by means of rotation in the sagittal plane; eversion and inversion of the ankle (36) by means of rotation in the lateral plane; and wherein each of these degrees of movement is actuated by means of an actuator (41, 42, 43, 44, 45, 46) respectively.

29. The exoskeleton for assisting human movement according to claim 28, wherein the mechanical structure comprises a shaft (120) eccentric with respect to the crossing of an upper segment (121) and a lower segment (122) of the knee joint, wherein said eccentric shaft (120) is actuated by the corresponding actuator (44), which define the degree of movement of flexion and extension of the knee (34) by means of rotation in the sagittal plane.

30. The exoskeleton for assisting human movement according to claim 28, wherein the mechanical structure comprises a bar mechanism (47) that receives the movement of the corresponding actuator (45) that is separate from the ankle of the user wherein the bar mechanism (47) transmits the movement to the ankle, and an elastic element (48) that exerts traction on the bars of the bar mechanism (47).

31. The exoskeleton for assisting human movement according to claim 27, wherein the mechanical structure comprises a condylar fitting mechanism (18) for passively fitting the condylar angle formed between the femur and tibia.

32. The exoskeleton for assisting human movement according to claim 31, wherein the condylar fitting mechanism (18) comprises a proximal segment (150) adjacent to a knee joint (105) and a distal segment (151) further away from the knee joint (105), wherein the proximal segment (150) is shorter and is introduced into the distal segment (151), and wherein both segments (150, 151) are joined by means of a pin (152) arranged in perpendicular direction to the tibia of the user and in the advance direction, and wherein a threaded mechanism arranged in the lower end of the distal segment (151) carries out the regulation of the condylar angle.

33. The exoskeleton for assisting human movement according to claim 31, wherein the condylar fitting mechanism (18) comprises a four-bar mechanism (110) arranged under the knee joint (105).

34. The exoskeleton for assisting human movement according to claim 27, wherein the fastening system (2) further comprises an ischiatic support (25), preferably an adjustable and removable girth, the tension of which is adjusted through a manual or automatic tensioning mechanism (26).

35. The exoskeleton for assisting human movement according to claim 27, wherein the fastening system (2) further comprises a device for permanently or detachably anchoring (28) to the shoe of the user.

36. The exoskeleton for assisting human movement according to claim 27, comprising: a. an on board power system (13) that provides energy to an actuation system made up of the actuators (41, 42, 43, 44, 45, 46) comprising the mechanical structure and a computing system (14); b. an on board sensory system (3) that monitors the movement of the exoskeleton and comprises at least one of the following subsystems: a proprioceptive subsystem (4), that instantly determines the state of the robot, a physiological subsystem (5), which determines the state of the user by means of biomarkers, an exteroceptive subsystem (6), which determines the state of the surroundings instantly or over a period of time, a perceptive subsystem (7) for the exoskeleton-user-surroundings interaction, which determines the state of the mutual interaction between the three previous subsystems (4, 5, 6); and c. a movement control system (12) that receives the information from the on board sensory system (3), and comprising one or more of the following subsystems: a joint control system (8), a limb control system (10), a control system of the center of mass of the exoskeleton-user assembly (11).

37. The exoskeleton for assisting human movement according to claim 36, wherein the joint control system (8) comprises an impedance control module that receives information from the sensory system (3), and in particular from the physiological subsystem (5), and automatically adapts the movement of the joint of the exoskeleton to the range, rigidity and spasticity of the equivalent joint of the user.

38. The exoskeleton for assisting human movement according to claim 36, wherein the movement control system (12) of each limb (10) synchronizes the joint control systems (8) that integrate the kinematic chain corresponding to that limb depending on the time, position and/or time derivatives thereof, and/or force and/or torque and/or time derivatives thereof, and/or depending on the information from the on board sensory system (3) in order to automatically adapt the movement of the limb to the rigidity conditions of the surroundings in contact.

39. The exoskeleton for assisting human movement according to claim 36, wherein the movement control system of the center of mass (11) of the exoskeleton-user assembly synchronizes the control systems of each limb (10) depending on the time and/or position and/or derivatives thereof and/or force and/or torque and/or derivatives thereof, or any other physical, mechanical or biomechanical variable and/or through the feedback of the information from the sensory system (3) and/or through the information ordered by the user by means of a user interface system (16) and/or following a movement reference pattern based on joint positions and/or derivatives thereof and/or torques and/or joint forces and/or positions of the limbs and/or derivatives thereof and/or forces and/or torques in the limbs and/or any biomechanical parameter, controlling the equilibrium of the user-exoskeleton assembly.

40. The exoskeleton for assisting human movement according to claim 36, comprising a user interface system (16) that interprets the movement intention of the user and transmits this information to the movement control system of the center of mass (11).

41. The exoskeleton for assisting human movement according to claim 40, comprising a communication system (15) that acts as a link between the control systems (8, 10, 11), the sensory system (3) and the user interface system (16) or between any combination thereof, and wherein one or more on board processing units carry out all the computational processing of one or more of the sensory (3), control (8, 10, 11) and user interface (16) systems.

42. The exoskeleton for assisting human movement according to claim 41, wherein the joints joining the segments of the mechanical structure comprise a joint range adjustable and adaptable to the joint range of the user, wherein this regulation is chosen from among: mechanical regulation through a stop or sliding brake, by means of threading or a by means of a linear displacement system, electronic regulation by means of limit sensors, programmed by establishing the joint limits to the joint control system (8) through the user interface system (16), and automatic regulation by determining the joint range of the user and communicating the joint limits to the joint control system (8) through the on board sensory system (3), or any combination of these.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] As a complement to the description provided herein, and for the purpose of helping to make the characteristics of the invention more readily understandable, a set of drawings is attached as an integral part of said description, which, by way of illustration and not limitation represent the following:

[0075] FIGS. 1a to 1c.—Show an embodiment of a lower limb exoskeleton with a user, in three views: profile, front and perspective, respectively. They indicate the elements of the fastening system of the user to the exoskeleton.

[0076] FIG. 2.—Shows the ischiatic support in the view on the left, and a manual adjustment system for the same in the detail on the right.

[0077] FIGS. 3a to 3d and 4a to 4c.—Show in detailed view of the retraction process of the rigid lumbar reinforcement.

[0078] FIG. 5.—Shows the degrees of joint movement and the corresponding actuators for an embodiment of a lower limb exoskeleton of 6 degrees of freedom per leg.

[0079] FIGS. 6a and 6b.—Show a variant of the invention with an extra degree of freedom that enables rotation of the knee in several positions.

[0080] FIG. 7a.—Shows a detailed view of the anchoring of the exoskeleton to the shoes.

[0081] FIG. 7b.—Shows a detail of the bar mechanism and elastic element that complements the ankle joint actuator.

[0082] FIG. 8.—Shows a lateral view of a lower limb exoskeleton and indicates a variable and controllable impedance actuator at the knee.

[0083] FIG. 9.—Shows a diagram of the control system.

[0084] FIGS. 10a and 10b.—Show the mechanical structure adapted to normal and abnormal anatomy, with a detail of the condylar fitting mechanism in different positions.

[0085] FIGS. 11a and 11b.—Show a variant of the invention for the adjusting the condylar angle, making use of a four bar mechanism in different positions.

PREFERRED EMBODIMENT OF THE INVENTION

[0086] The exoskeleton for assisting human movement of the present invention is described in a detailed manner below.

[0087] The exoskeleton comprises a modular mechanical structure comprising segments joined by joints. Said mechanical structure comprises an abduction/adduction joint at the hip (32), adjustable by means of an actuator (42) that allows for obtaining a range of cervical diaphysiary angles within the desired ranges for patients with anti-physiological gait, due to anatomical anomalies, such as hips with abnormal cervical diaphysiary angles.

[0088] The mechanical structure further comprises a condylar fitting mechanism (18) that allows for passively fitting the condylar angle formed between the femur and tibia in order to adapt it to users with anatomical anomalies such as bow-leggedness or knock-knees. FIGS. 10a and 10b show a first exemplary embodiment of said condylar fitting mechanism (18) comprising a proximal segment (150) adjacent to a knee joint (105) and a distal segment (151) further away from the knee joint, wherein the proximal segment (150) is shorter and is introduced into the distal segment (151), and wherein both segments (150, 151) are joined by means of a pin (152) arranged in perpendicular direction to the tibia of the user and in the advance direction, wherein the adjustment of the condylar angle is carried out by means of a threaded mechanism arranged in the lower end of the distal segment. FIG. 10 shows the mechanical structure of the exoskeleton for a user without anomalies and FIG. 10b shows the mechanical structure fitted fora user with coxa vara and genu valgum.

[0089] The exoskeleton comprises 6 degrees of movement in each leg, which are actuated. These degrees of movement are the following: [0090] Flexion and extension of the hip (31) by means of rotation in the sagittal plane; [0091] Abduction-adduction of the hip (32) by means of rotation in the lateral plane; [0092] Rotation of the hip (33) by means of rotation in the transverse plane; [0093] Flexion and extension of the knee (34) by means of rotation in the sagittal plane;

[0094] Flexion and extension of the ankle (35) by means of rotation in the sagittal plane; [0095] Eversion and inversion of the ankle (36) by means of rotation in the lateral plane;
each actuated by means of an actuator (41, 42, 43, 44, 45, 46) respectively.

[0096] The degree of movement for carrying out flexion and extension of the knee (34) by means of rotation in the sagittal plane is defined because the mechanical structure comprises a shaft (120) that is eccentric with respect to the crossing of an upper segment (121) and a lower segment (122) eccentric shaft (120) actuated by the corresponding actuator (44), which allows a flexion above 100°, required for sitting, and provides greater stability in the support, as shown in FIG. 1.

[0097] FIGS. 11a and 11b show a second exemplary embodiment, wherein the condylar fitting mechanism (18) comprises a four-bar mechanism (110) arranged under the knee joint (105). In this way the upper segment (121) is shifted, although it is kept parallel to the inner segment (122), varying the condylar angle and fitting it to the user.

[0098] The degree of movement for carrying out the flexion and extension of the ankle (35) by rotation in the sagittal plane comprises an actuator (45) separate from the ankle of the user that transmits the movement to the ankle through a bar mechanism (47) and an elastic element (48) that exerts traction on the bars of the bar mechanism (47), wherein the effect of the elastic element is to constantly contribute to the plantar flexion of the ankle. The combined operation of the actuator (45) and elastic element (48) is as follows: during the support, the user's weight and the action of the actuator (45) overcome the counter-torque generated by the elastic element (48) and the phase is executed normally. Upon reaching the lift-off phase, the effect of the user's weight disappears, while the actions of the elastic element (48) and actuator (45) combine in favor of the plantar flexion, which generates the instantaneous power required for the impulse. During the foot transfer phase, the actuator (45) has enough power to counteract the effect of the elastic element (48) and generate the dorsal flexion of the ankle to prevent impact with the ground. FIG. 7b details an implementation of the ankle joint and its position during the support phase and during the impulse.

[0099] The exoskeleton comprises a fastening system (2) that allows it to carry out its coupling to the human body from the front of the body, allowing its positioning from a sitting or lying position without requiring a functional transfer.

[0100] The fastening system (2) comprises a rigid lumbar reinforcement (20) that in turn comprises two or more segments that are able be coupled (21), as shown in FIGS. 3a to 3d, two of which are joined to the segments of the exoskeleton by means of one or more rotation shafts (22), wherein the rigid lumbar reinforcement (20) is retracted by means of successive rotations until it is located in the sagittal plane in order to allow positioning the exoskeleton from the front of the user. Once the exoskeleton is coupled to the user, the segments that make up the rigid lumbar reinforcement (20) are turned back again until they reach their functional lumbar position, the segments being secured to each other by means of a coupling system (23). FIGS. 4a to 4c show a view of the rigid lumbar reinforcement (20) in two different positions: FIG. 4a shows the natural operating position of the lumbar reinforcement (20), in which both segments that are able to be coupled (21) are connected and occupy the rear portion of the exoskeleton. FIGS. 4b and 4c show the retraction sequence until both segments that are able to be coupled (21) are completely stowed parallel to the sagittal plane, leaving the inner space completely free inside the exoskeleton in order to proceed to its positioning from the front of the user.

[0101] This positioning method exploits the modularity of the design of the exoskeleton, each of the limbs being able to be placed independently and finally joining through the lumbar reinforcement (20) and the rest of the components of the fastening system (2).

[0102] The fastening system (2) further comprises an ischiatic support (25) the function of which is to transfer the user's weight to the exoskeleton, wherein said ischiatic support is preferably a girth located under the buttocks of the user, which supports a part or all of the user's weight and transmits it to the mechanical structure, as seen in FIG. 2. Said ischiatic support (25) is adjustable, the tension thereof being can be adjusted through a tensioning mechanism (26) that can be manual or automatic, apart from being removable, which results in the easy placement of the exoskeleton. In order to not obstruct the positioning of the exoskeleton, the ischiatic support (25) can buckle and unbuckle, depending on the positioning method of the exoskeleton.

[0103] The ischiatic support (25) can also be carried out by means of thermoplastic thigh pieces, especially in those patients with low bone density like osteoporosis.

[0104] The fastening system (2) further comprises fastening devices for securing the exoskeleton to the legs of the user, not being rigid in their back portion in order not to obstruct the positioning of the exoskeleton on the human body from the front of the body.

[0105] The fastening system further comprises a device for anchoring (28) to the shoe of the user, which is carried out permanently, by means of rivets or another fastening system, or detachably by means of screws or other fitting means, on the inside of the shoe or on the outside. Since most patients need to use orthopedic footwear, the use of exoskeletons with a sole to which the user's shoe is fitted is not recommended; it is preferable that the mechanical structure be anchored directly over the natural sole of the footwear, so as to not interfere with the pathology of the foot. FIGS. 7a and 7b show an exemplary embodiment of the anchoring of the exoskeleton to the shoe of the user, wherein brace-type fastening is used on the heel of the sole and is clamped by means of screws or rivets (28).

[0106] The exoskeleton comprises an on board power system (13) that provides energy to an actuation system made up of the actuators (41, 42, 43, 44, 45, 46) comprising the mechanical structure and a computer system (14).

[0107] The exoskeleton further comprises an on board sensory system (3) that monitors the movement of the exoskeleton and comprises: [0108] e. A proprioceptive subsystem (4) that instantly determines the state of the robot, [0109] f. A physiological subsystem (5), which determines the state of the user by means of biomarkers, [0110] g. An exteroceptive subsystem (6), which determines the state of the surroundings instantly or over a period of time, [0111] h. A perceptive subsystem (7) for the exoskeleton-user-surroundings interaction, which determines the state of the mutual interaction between the three previous subsystems (4, 5, 6),
being able to include all, some or any combination of these subsystems (4, 5, 6, 7).

[0112] The exoskeleton comprises a movement control system (12) that receives the information from the on board sensory system (3), and which is composed of one or more of the following subsystems: [0113] a. Joint control system (8). [0114] b. Limb control system (10). [0115] c. Control system of the center of mass of the exoskeleton-user assembly (11).

[0116] The joint control system (8) guarantees the desired joint movement in the user based on the tracking of a reference signal that can be any physical, mechanical or biomechanical magnitude such as joint position, speed, force, torque or any derivative or combination thereof, by means of an automatic control technique (Proportional, Integral, Derivative, neuronal control, diffuse control, heuristic control, non-linear control, robust control, optimal control, etc., or any combination thereof).

[0117] Given that most exoskeleton users have spasticity, spasms and other anomalies, it is necessary to adapt the joint movement to said effects in order to avoid damaging the tendinomuscular tissue of the user. To do so, the joint control system (8) incorporates an impedance control module that receives information from the sensory system (3) and in particular from the physiological subsystem (5) and automatically adapts the movement of the joint of the exoskeleton to the range, rigidity and spasticity of the equivalent joint of the user. In some embodiments of the invention, this impedance control module can be implemented by means of a variable and controllable impedance joint, as described in the application for Spanish patent P201330882 included herein as a reference, which has important advantages as compared to programmed modules. FIGS. 6a and 6b show an embodiment of the invention that incorporates a variable and controllable impedance joint (50) in the knee.

[0118] The movement control system of each lower limb (10) synchronizes the joint control systems (8) that integrate the kinematic chain corresponding to that limb depending on the time, position and/or time derivatives thereof, and/or force and/or torque and/or time derivatives thereof, and/or depending on the information from the sensory system in order to automatically adapt the movement of the lower limb (10) to the rigidity conditions of the surroundings in contact.

[0119] The movement control system of the center of mass (11) of the exoskeleton-user assembly synchronizes the control systems of each lower limb (10) depending on the time and/or position and/or derivatives thereof and/or force and/or torque and/or derivatives thereof, or any other physical, mechanical or biomechanical variable and/or through the feedback from the information from the on board sensory system (3) and/or through the information ordered by the user by means of a user interface system (16) and/or following a movement reference pattern based on joint positions and/or derivatives thereof and/or torques and/or joint forces and/or positions of the lower limbs (10) and/or derivatives thereof and/or forces and/or torques in the lower limbs (10) and/or any biomechanical parameter.

[0120] FIG. 9 shows an exemplary embodiment of the movement control system (12) for an exoskeleton with 4 limbs, two arms and two legs, and 6 joints per limb.

[0121] The movement control system of the center of mass (11) has the ability to adapt the reference patterns to the biomechanical conditions of the user, by means of an automatic reference pattern adapter. This automatic reference pattern adapter fits said movement patterns to the joint range, muscle strength and instantaneous conditions of each limb of the user.

[0122] This movement control system of the center of mass (11) maintains the exoskeleton-user assembly in dynamically or statically stable equilibrium even in the face of slight external disturbances. Equilibrium control is carried out based on the tracking of a desired stability index, which can be based on the nominal trajectory of the Pressure Center or of the Zero Moment Point (ZMP), on the Normalized Dynamic Energy Stability Margin (NDESM), or any other stability index. Based on an instantaneous measuring of said index and comparing it to the desired or par value, the difference between both values is minimized by means of any control technique (proportional, derivative, integral, blurry, neuronal, optimal etc. or any combination thereof) by means of the generation of a movement or a torque in the center of mass of the robot-user assembly or in any of its limbs. The control system of the center of mass (11) will determine if it is necessary to modify the gait pattern in order to maintain equilibrium.

[0123] The joint control system (8), the movement control system of each limb (10), and the movement control system of the center of mass (11) can be combined with a human actuation system whereby the muscles of the user participate in a certain degree in the generation of movement. This human actuation system can be carried out directly by means of the voluntary movement of the user, or indirectly by means of functional electrical stimulation (FES) or a combination of both. These control systems can also be combined or synchronized with a central pattern generator (CPG).

[0124] The user interface system (16) that interprets the movement intention of the user and transmits this information to the movement control system. This user interface system (16) can be made up of a joystick, tablet, mobile phone, touch screen, keyboard, mouse, microphone, camera, eye-movement reader, electromyography sensors (EMG), brain-computer interfaces (BCI), electrooculography interfaces (EEG), force or torque sensors, pressure sensors, inertial measurement units (IMU), position, speed or inclination sensors, etc., or any combination of these devices, and includes the electronics and the information processing required for the user interface system (16) to capture the movement intention of the user.

[0125] The exoskeleton comprises a communication system (15) that acts as a link between the control systems (8, 10, 11), the sensory system (3) and the user interface system (16) or between any combination thereof. This communication can be wired, wireless or any combination of both, by means of any communication protocol (CAN, Ethernet, LAN, etc.).

[0126] The exoskeleton further comprises one or more on board processing units that carry out all the computational processing of one or more of the sensory (3), user movement control (8, 10, 11) and user interface (16) systems. The processing units can be based on any type of processor, microprocessor, field-programmable gate array (FPGA) or any combination thereof.

[0127] All of the processing electronics, as well as the on board power source of the exoskeleton is placed throughout the mechanical structure. If the power source is based on rechargeable or replaceable batteries, these are located in the lateral and front portion of the exoskeleton in order to facilitate their charging or replacement by the user.

[0128] The joints joining the segments of the mechanical structure of the exoskeleton of the present invention comprise a joint range adjustable and adaptable to the joint range of the user. This regulation can be mechanical, electronic, programmed or automatic, or any combination of these. [0129] a. Mechanical: by means of a stop or sliding brake, by means of threading or by means of any other linear displacement system. [0130] b. Electronic: by means of the use of limit sensors or any similar device that detects the limit joint position and commands stopping the joint motor. [0131] c. Programmed: the user or another responsible person (a medical professional) establishes the joint limits to the joint control system (8) through the user interface system (16). [0132] d. Automatic: the exoskeleton, through the on board sensory system (3), determines the joint range of the user and communicates the joint limits to the joint control system (8) preferably as part of a self-check program.
or any combination of these.