DEVICE FOR PHYSICAL EXERCISE

Abstract

To improve the dynamic response, a method is described for managing a physical exercise device (10) comprising an endless belt (16) to create a track on which a user (U) can walk or run, and an electric motor (30) to slide the belt.

The method has the steps of controlling the driving torque applied by the electric motor (30) to the belt (16) so that the driving torque is proportional to the force component (F), or to the torque, which the user imparts on the belt (16) to advance on the belt (16).

Claims

1. Method for managing a physical exercise device (10) comprising an endless belt (16) to create a track on which a user (U) can walk or run, and an electric motor (30) to slide the belt, with the steps of controlling the driving torque applied by the electric motor (30) to the belt (16) so that the driving torque is proportional to the force component (F), or to the torque, which the user imparts on the belt (16) to advance on the belt (16).

2. Method according to claim 1, wherein the driving torque is regulated to transmit to the belt a force or torque that has equal direction as said force or torque generated by the user.

3. Method according to claim 1, wherein the driving torque is regulated to transmit to the belt a force or torque having opposite direction to that of said force or torque generated by the user.

4. Physical exercise device (10) comprising: an endless belt (16) to create a track on which a user (U) can walk or run, an electric motor (30) to slide the belt, a sensor (22) for generating an electrical signal indicative of the force component, or indicative of the torque, that the user imparts on the belt for advancing on the belt, an electronic circuit (40) configured for reading the sensor's signal, and controlling the driving torque applied by the electric motor (30) to the belt (16) so that the driving torque is proportional to said component or said torque imparted by the user.

5. Device according to claim 4, wherein the electronic circuit (40) is configured to regulate the driving torque so as to transmit to the belt (16) a force or torque that has same direction as said force or torque generated by the user.

6. Device according to claim 4, wherein the electronic circuit (40) is configured to regulate the driving torque so as to transmit to the belt (16) a force or torque having opposite direction to that of said force or torque generated by the user.

7. Device according to claim 4, wherein the sensor (22) is configured to detect a force imparted by the user along a direction (F) parallel to the sliding direction of the belt and/or a direction parallel to that of the supporting surface (T) on which the device is placed.

8. Device according to claim 4, wherein the sensor (22) is placed at a point located between the device and the supporting surface (T), and/or on and/or below the surface of the belt, and/or on the user's shoes.

9. Device according to claim 4, wherein the sensor (22) is a load cell, or a strain gauge or a pressure sensor.

10. Device according to claim 4, comprising a low-pass filter for filtering the signal generated by the sensor before sending it to the electronic circuit.

Description

[0047] Further advantages will become apparent from the following description, which refers to a preferred embodiment in which:

[0048] FIG. 1 shows a diagram of a treadmill.

[0049] A treadmill 10 is illustrated schematically in FIG. 1, and comprises a base frame 14 on which are mounted two rollers 12 which support a well-known endless belt 16 on which a user U can place his feet P in the act of walking or running on the spot.

[0050] The base frame 14 rests on a floor T through feet 18, on or in or under which are mounted one or more load cells 22.

[0051] At least one of the two rollers 12 is coupled with an electric motor 30 for receiving rotary motion and move the belt 16.

[0052] The electric motor 30 is controlled by a microprocessor 40 through known power electronics stages (not shown), e.g. an inverter. The arrows in FIG. 1 indicate signal lines.

[0053] The microprocessor 40 is also connected to the load cells 22, to read the emitted signals therefrom, and to an (optional) data input user interface 50, e.g. a touchscreen. Through the user interface 50 the user can program a proportionality constant, useful for adjusting the operation of the treadmill 10.

[0054] The cells 22 are installed so as to emit a signal indicative of the force that a foot P of a user U exerts onto the belt 16 during the exercise. From the measured force the weight of the user U is disregarded, while only the component F parallel to the surface of the belt 16 and/or to the surface of the floor T is considered. One may also measure a different force or at different points, and extract or calculate therefrom the component F parallel to the belt surface 16 and/or to the floor T's surface.

[0055] The cells 22 may be replaced by any sensor capable of generating an electrical signal proportional to or indicative of the component of the thrust generated by the foot P which, on the floor T and without the treadmill 10, would move the user U's body forward. To this force, as explained below, the device reacts by generating a proportional force or torque on the belt 16.

[0056] In the microprocessor 40 the signal generated by the cells 22 is compared in a circuit 42 with a signal which expresses the proportionality constant entered with the user interface 50. The comparison is e.g. a subtraction to generate an error term.

[0057] The result of the circuit 42 is processed by a gain stage 44 which emits control signals for the electric motor 30 so that the latter develops a certain torque and imposes a force to the endless belt 16 in dependence of the signal emitted by the circuit 42.

[0058] Preferably, for greater accuracy, the electric motor 30 is also feedback controlled thanks to a signal line 32 which returns to the stage 44 a feedback signal from the electric motor 30.

[0059] As it can be seen, the microprocessor 40 implements a feedback control in which the proportionality constant entered with the user interface 50 becomes a reference signal for adjusting the torque imparted by the electric motor 30 to the endless belt 16. Then, according to the value of this proportionality constant, the electric motor 30 can impart to the endless belt 16 a force opposite to that imparted by a foot P (resistance to the stride), or a force in the same direction (assistance to the stride).

[0060] In another exemplary embodiment, the circuit 42 is a multiplication block, in which the signal coming from the cells 22 is multiplied by the constant of proportionality. The result of the multiplication is input to the stage 44 as a torque reference for the motor 30. The stage 44 then acts on the motor 30 for making it develop a torque which tracks the reference.

[0061] Since the cells 22 generate a pulse signal, with peaks having cadence of the stride, it is preferable to filter it with a low pass filter 52, e.g. a digital filter implemented numerically in the microprocessor 40. Thus, the torque reference for the motor 30 has a less oscillatory trend.