A mechanical arm system includes at least two links, at least two control devices and at least two motor devices. Each of the control devices includes a first control unit, a mechanical arm control unit and a driving unit. The first control unit receives an end-position command to output a first torque signal. The mechanical arm control unit includes a rigid mechanical unit and a mechanical model unit. The rigid mechanical unit receives the first torque signal to obtain a rigid mechanical torque, and the mechanical model unit receives the rigid mechanical torque and operates the flexible mechanical model to establish the mechanical arm model for obtaining the target torque, and the target position signal is output according to the target torque. The driving unit generates a driving signal according to the target position signal to adjust a rotation angle of the corresponding motor device.

A drive unit 10A is configured to exert a driving force on an environment 50 in accordance with a target driving force command τ.sub.d, and includes a parameter storage device 30A, a force measuring instrument 35, an admittance model calculation device 31A, and a position control and driving device 33A. The parameter storage device 30A has stored therein dynamics parameters of first and second virtual objects affected by a virtual interactive force λ.sub.R. The force measuring instrument 35 is configured to output a measurement result for the driving force as a measured driving force value τ.sub.s. The admittance model calculation device 31A is configured to calculate and output a displacement of the first virtual object. The displacement is obtained by calculations based on the stored dynamics parameters, the target driving force command τ.sub.d, and the measured driving force value τ.sub.s. The position control and driving device 33A is configured to operate in accordance with a target position command. The force measuring instrument 35 is disposed between the position control and driving device 33A and the environment 50. The target position command corresponds to the first virtual object's displacement outputted by the admittance model calculation device 31A. The drive unit 10A achieves advantages of both high and low backdrivability.

Implementations are directed to, for each of one or more joints of a robot, generating dynamic joint torque saturation limits for the joint, such as an upper joint torque saturation value and a lower joint torque saturation value. Implementations are additionally or alternatively directed to utilizing the dynamic torque saturation limits for the joint in generating driving torques and/or to driving a motor (or other actuator) of the joint based on the driving torques. Various implementations can enable regulation of contact forces for a robot in situations where the robot lacks joint torque sensor(s) and/or force torque sensor(s) and/or in situations where such sensor(s) are present, but have failed or are malfunctioning.

A method for estimating a wrench acting on a reference point of a robot includes the steps of: a) measuring at least one component, but not all components, of the wrench; and b) estimating non-measured components of the wrench based on a dynamical model of the robot while taking into account the measured components.

A method for estimating a wrench acting on a reference point of a robot includes the steps of: a) measuring at least one component, but not all components, of the wrench; and b) estimating non-measured components of the wrench based on a dynamical model of the robot while taking into account the measured components.

A mechanical arm system includes at least two links, at least two control devices and at least two motor devices. Each of the control devices includes a first control unit, a mechanical arm control unit and a driving unit. The first control unit receives an end-position command to output a first torque signal. The mechanical arm control unit includes a rigid mechanical unit and a mechanical model unit. The rigid mechanical unit receives the first torque signal to obtain a rigid mechanical torque, and the mechanical model unit receives the rigid mechanical torque and operates the flexible mechanical model to establish the mechanical arm model for obtaining the target torque, and the target position signal is output according to the target torque. The driving unit generates a driving signal according to the target position signal to adjust a rotation angle of the corresponding motor device.

The present disclosure provides a joint control method for a serial robot and a serial robot using the same. The method includes: performing a analysis on an end joint in the plurality of joints, and calculating the force of the previous joint acting on the end joint; performing a analysis on each of the other joints in the plurality of joints, and calculating the force of the previous joint acting on the joint; obtaining an angular velocity and an angular acceleration of each joint after obtaining the force of the previous joint acting on the joint, and calculating a torque corresponding to each joint; and projecting the torque corresponding to each joint to a motor corresponding to the joint to obtain a torque to be applied to the motor at a current time. In this manner, which improves the tracking precision of the end joint while reduces the tracking error.

A method is provided for absolute position determination of the end effector of a robotic device with a kinematic chain of movable components. At least one current torque or one value corresponding to the torque is measured on at least one movable component of the kinematic chain of the robotic device by a torque sensor arranged on the movable component. At least one torque is calculated on the basis of model data of the robotic device for the movable component. A difference between the measured torque and the calculated torque is determined. If the difference exceeds a prespecified threshold value, the at least one measured torque is used instead of the calculated torque to determine an absolute position of the end effector of the robotic device.

The present disclosure provides a joint control method for a serial robot and a serial robot using the same. The method includes: performing a analysis on an end joint in the plurality of joints, and calculating the force of the previous joint acting on the end joint; performing a analysis on each of the other joints in the plurality of joints, and calculating the force of the previous joint acting on the joint; obtaining an angular velocity and an angular acceleration of each joint after obtaining the force of the previous joint acting on the joint, and calculating a torque corresponding to each joint; and projecting the torque corresponding to each joint to a motor corresponding to the joint to obtain a torque to be applied to the motor at a current time. In this manner, which improves the tracking precision of the end joint while reduces the tracking error.

A method is provided for absolute position determination of the end effector of a robotic device with a kinematic chain of movable components. At least one current torque or one value corresponding to the torque is measured on at least one movable component of the kinematic chain of the robotic device by a torque sensor arranged on the movable component. At least one torque is calculated on the basis of model data of the robotic device for the movable component. A difference between the measured torque and the calculated torque is determined. If the difference exceeds a prespecified threshold value, the at least one measured torque is used instead of the calculated torque to determine an absolute position of the end effector of the robotic device.