Electric resistance control method of strength training apparatus

Abstract

The invention relates to the technical field of training instruments, in particular to an electric resistance control method of a strength training instrument, and the method comprises the steps: obtaining a real-time tension value of a pull rope to an electric resistance source through a force sensor; calculating the due acceleration of the pull rope under the real-time tension value based on the real-time tension value and a first formula; calculating the size and the direction of the due speed based on the condition that the initial speed is zero and due acceleration at historical moments are superposed; and performing conversion based on the due speed to obtain operation parameters of the electric resistance source at the current moment and outputting the electric resistance. The electric resistance source has self-locking force and cannot be pulled by the pull rope, due acceleration and due speed are calculated through pulling force and simulation mass, so that operation parameters of the electric resistance source are obtained, the passive rotation mode of a traditional non-self-locking electric resistance source is changed to present active operation, real simulation of the balancing weight can be achieved, and the simulation efficiency is improved. Especially, inertia simulation and real-time feedback simulation are included, and the body feeling of real balancing weight training is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of training equipment, and in particular to an electric resistance control method of a strength training equipment. The electric resistance of the strength training equipment is controlled by a servo system. Background Art

[0002] The basic principle of traditional strength training equipment is that one end of the pull rope is connected to the operating part such as the handle, foot pedal, pad, etc., and the other end of the pull rope is connected to the weight system. The pull rope passes through the pulley set, and the user operates the operating part, and the weight system is pulled up or down, and the muscles are trained by resisting the resistance of the weight block. However, during the use of this type of traditional strength training equipment, if the user wants to adjust the weight block, he needs to stop using the equipment before adjusting it. At the same time, the pin can only be adjusted manually, and the weight adjustment can only be adjusted at a fixed value. The trainee cannot adjust the resistance in real time according to his own needs.

[0003] China's open patent document (CN107233694A) discloses a new type of intelligent strength training device, which has a frame, a synchronous pivot is pivoted on the frame, a large synchronous wheel and a pulley are fixed on the synchronous pivot, one end of the belt wound on the pulley is fixed on the pulley and the other end is connected to the operating part, a servo rotary motor is fixed on the frame, a small synchronous wheel is fixed on the motor shaft of the servo rotary motor, the synchronous belt is wound on the large synchronous wheel and the small synchronous wheel, the servo rotary motor is connected to the driver and controlled by the controller, and the torque sensor and speed sensor installed on the servo rotary motor shaft are connected to the controller. The fitness person operates the operating part (by hand pulling, foot stepping, leg clamping, etc.), pulls the belt, and the belt drives the pulley to rotate, and then drives the large synchronous wheel and the small synchronous wheel to rotate, and the small synchronous wheel drives the motor shaft of the servo rotary motor to rotate, and the servo rotary motor is preset with resistance by the controller, and the fitness person operates the operating part to overcome the resistance and drive the servo rotary motor to rotate.

[0004] This intelligent strength trainer uses a servo rotary motor to replace the bulky counterweights, and adjusts the muscle training resistance through an electronic meter. The resistance adjustment is convenient. Its working principle is that the force applied by the user to the servo rotary motor causes the speed of the servo rotary motor to change. Different output forces are obtained by changing the preset maximum speed or power. The torque T, the actual output power P and the motor speed n satisfy the following formula: T=9550×P / n.

[0005] However, the servo rotary motor here must use a non-self-locking reducer, so that the reel can be pulled by a person, and then pull the servo rotary motor, that is, the servo rotary motor is pulled by a person to rotate and its speed is determined by the pulling speed of the person. This results in the inability to fully meet the effect of simulating the counterweight block, because at this time, when a person changes the output size, changing the motor speed does not require overcoming the inertia of the counterweight block; and when pulling the counterweight block, changing the pulling speed requires overcoming the inertia of the counterweight block, which leads to a difference between the physical sensation of simulating pulling the counterweight block and the physical sensation of the actual counterweight block. Furthermore, since the output power of a person changes all the time, and the existing trainer cannot sense the actual output power of a person in real time, the output force of the servo rotary motor is uncontrollable, which also makes it impossible to simulate the effect of the counterweight block.

[0006] In addition, when the rope is pulled to recover, the servo rotary motor and the person recover together. Because the recovery torque must overcome the resistance caused by the system, the torque during recovery must be large enough. However, since the size of the torque is determined by the power and speed, the following two contradictory situations will be caused: First, if the recovery speed of the rope is fast, the recovery force will be very small and cannot overcome the resistance, and the servo rotary motor will not be able to rotate; second, if the recovery torque of the rope is large, the speed will be slow and cannot keep up with the speed of the human hand, which will cause the physical sensation to be very unreal and very poor.

[0007] In summary, the working mode of the servo strength trainer in the prior art cannot completely simulate the inertia of the counterweight block, and cannot simulate the change of the actual output force of the counterweight block after the force applied by a person changes. Summary of the invention

[0008] The object of the present invention is to provide an electric resistance control method for a strength training device, which can simulate the inertia of a real counterweight block and achieve the physical sensation of real counterweight block training.

[0009] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: The electric resistance control method of the strength training device specifically comprises the following steps: S1. Using a force sensor to obtain a real-time pulling force value of the pull rope on the electric resistance source, the pull rope serves as a force transmission component between the electric resistance source and the training operation part; S2, based on the real-time tension value of step S1 and the first formula, calculate the required acceleration a of the pull rope under the real-time tension value; The first formula is a=(F1-m×g+dir×f) / m, where: F1 is the real-time tension value of the pull rope, m is the simulated mass of the electric resistance source, f is the system resistance, dir is -1 when the pull rope is pulled out and +1 when the pull rope is retracted; S3, based on the initial velocity of zero and the acceleration that should have occurred at the historical moment, the magnitude and direction of the velocity of the rope at the current moment are calculated; S4, converting the required speed in step S3 to obtain the current operating parameters of the electric resistance source and outputting the electric resistance according to the operating parameters; The electric resistance source has a self-locking force.

[0010] Preferably, the force sensor in step S1 is installed in the transmission path of the pull rope.

[0011] Preferably, a fixed pulley is provided in the transmission path of the pull rope, and the force sensor is circular and coaxially mounted on the end of the central axis of the fixed pulley.

[0012] Preferably, the force sensor is a pressure sensor.

[0013] Preferably, the real-time tension value F1 of step S1 and the force value F0 measured by the force sensor satisfy the following relationship: F0=2F1×CosA; wherein CosA is the cosine value of the angle A between the resultant force line of the force sensor and the pull rope at the fixed pulley.

[0014] Preferably, the electric resistance source is a speed-controllable rotary motion device or a linear motion device equipped with a servo system.

[0015] Preferably, the electric resistance source includes an electric cylinder equipped with a servo system, a linear motor and a rotary motor.

[0016] Preferably, the electric resistance source adopts a combination of a servo rotary motor and a reducer and a winding wheel is provided on the output shaft of the self-locking reducer, one end of the pull rope is wound on the winding wheel, and the conversion method of step S4 is: based on the expected speed, the diameter of the winding wheel and the transmission ratio of the reducer, the speed and direction of the servo rotary motor are calculated.

[0017] Preferably, the superposition calculation adopts numerical integration approximate calculation, and the formula is: ; Where: a(t i-1 ) is t i-1 The acceleration at a moment, a(t i ) is t i The acceleration of time.

[0018] Preferably, the self-locking reducer is a worm gear reducer.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The electric resistance source of the present invention has a self-locking force and will not be pulled by the pull rope. The required acceleration and speed when the tension pulls the simulated mass are calculated by the tension and the simulated mass, thereby obtaining the operating parameters of the electric resistance source. No speed sensor or acceleration sensor is required, and the passive rotation mode of the traditional non-self-locking electric resistance source is changed to active operation. The real simulation of the counterweight block can be realized, especially the simulation of inertia and the simulation of real-time feedback, so as to achieve the physical sensation of real counterweight block training. These are two points that similar products cannot do.

[0020] The electric resistance control method of the present invention is applicable to speed-controllable rotary motion devices equipped with a servo system, such as rotary motors, and linear motion devices, such as electric cylinders and linear motors. The servo system is a closed-loop control system composed of a controller, a feedback device, and a driver. Specific equipment applications include but are not limited to seated chest press machines, seated rowing machines, seated leg curling and extension machines, high pull-down machines, adduction / abduction training machines, abdominal curling machines, shoulder press machines, etc.

[0021] In addition, the control method of the present invention can be seamlessly connected to any weight training equipment that is connected to the original weight block, without the need for additional programming and debugging, while the traditional servo force system requires different programs and parameters to adapt to different devices.

[0022] Furthermore, the maximum output power of a person is 3KW, and the electric resistance source of the present invention has a self-locking force, which can offset a part of the output force of the person. Therefore, the electric resistance source of the present invention can use a smaller power, for example, the power of the servo rotary motor can be 1.2KW. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the seated leg flexion and extension machine of the present invention.

[0024] Figure 2 It is a schematic diagram of the internal structure of the counterweight box of the present invention.

[0025] Figure 3 It is a schematic diagram of the installation of the force sensor of the present invention at the fixed pulley.

[0026] Figure 4 It is a schematic diagram of the mechanical analysis between the force sensor of the present invention and the tension of the pull rope.

[0027] Figure 5 This is a flow chart of the electric resistance control of the strength training apparatus of the present invention.

[0028] Markings in the figure: 101, seat; 102, flexion and extension operating part; 103, counterweight box; 11, servo rotation motor; 12, worm gear reducer; 13, winding wheel; 14, servo drive; 15, touch screen controller; 16, pull rope; 17, force sensor; 18, fixed pulley. DETAILED DESCRIPTION

[0029] like Figure 5 As shown, the present embodiment provides an electric resistance control method for a strength training device, which is specifically applied to a seated leg curling machine, and specifically includes the following steps: S1, using a force sensor 17 to obtain a real-time tension value of the pull rope 16 on the electric resistance source; S2, based on the real-time tension value of step S1 and the first formula, calculating the required acceleration a of the pull rope 16 under the real-time tension value; S3, based on the initial speed being zero and the required acceleration at historical moments, calculating the required speed magnitude and direction of the pull rope 16 at the current moment; S4, based on the required speed of step S3, converting the operating parameters of the electric resistance source at the current moment and outputting the electric resistance with the operating parameters.

[0030] like Figures 1 to 3 As shown, the seated leg curling machine of this embodiment includes a weight box 103, an electric resistance source arranged inside the weight box 103, a frame, a seat 101 installed on the frame, and a curling operation unit 102. The curling operation unit 102 serves as a training operation unit of the seated leg curling machine. The electric resistance source includes a servo rotary motor 11, a worm gear reducer 12, and a winding wheel 13 installed on the output shaft of the worm gear reducer 12. The transmission ratio between the servo rotary motor 11 and the worm gear reducer 12 is 15, and the diameter of the winding wheel 13 is 104 mm. The servo rotary motor 11 is electrically connected to a servo driver 14, and the servo driver 14 is electrically connected to a touch screen controller 15. In addition, the servo rotary motor 11 has a built-in feedback device. The touch screen controller 15, the servo driver 14, the feedback device and the servo rotary motor 11 constitute a servo system.

[0031] It should be noted that in some other examples, the electric resistance source can also adopt other speed-controllable rotary motion devices or linear motion devices equipped with servo systems. The linear motion devices include servo electric cylinders or servo linear motors, etc., and the resistance source can be equipped according to different training equipment.

[0032] The seated leg curling machine of this embodiment also includes a pull rope 16 and a force sensor 17. The pull rope 16 serves as a force transmission component between the electric resistance source and the training operation part. One end of the pull rope 16 is fixed to the curling operation part 102, and the other end is wound around the pulley group and then wound on the winding wheel 13. The resistance output by the electric resistance source acts on the pull rope 16. Wherein: the pulley group includes a fixed pulley 18 installed inside the counterweight box 103, and the fixed pulley 18 is installed on the pulley bracket through the central axis. The type of the force sensor 17 is a pressure sensor, which is a circular structure, coaxially installed at the end of the central axis of the fixed pulley 18 and fixed on the pulley bracket, so that the real-time pulling force value of the pull rope 16 on the electric resistance source during the training process can be measured. It should be noted that the position of the force sensor 17 can also be other positions in the transmission path of the pull rope 16, and it is not limited to using a circular force sensor.

[0033] like Figure 4 As shown, the force value actually measured by the force sensor 17 is the resultant force of the pull rope 16 on the central axis of the fixed pulley 18 during the flexion and extension process. The tension value of the pull rope 16 at each location is consistent, and the front and rear angles of the pull rope 16 at the fixed pulley 18 will not change with the flexion and extension movement after assembly. The angle A between the resultant force line of the force sensor 17 and the pull rope 16 at the fixed pulley 18 is fixed and unchanged, and the angle value of the angle A can be preset in the touch screen controller 15.

[0034] In step S1, the real-time tension value F1 of the pull rope 16 and the force value F0 measured by the force sensor 17 satisfy the following relationship: F0=2F1×CosA; wherein CosA is the cosine value of the angle A between the resultant force line of the force sensor 17 and the pull rope 16 at the fixed pulley 18. The force sensor 17 has a measurement cycle of 0.001 seconds, so a real-time tension value can be obtained every 0.001 seconds, and these values ​​can be combined into an actual tension curve.

[0035] In step S2, when the real-time tension value F1 has been obtained, the real-time acceleration can be obtained according to the first formula based on the system resistance f measured in the uniform return process of the electric resistance source under the no-load state in the previous stage, one value every 0.001 seconds, and these values ​​can be combined into a real-time acceleration curve. The first formula is a=(F1-m×g+dir×f) / m, where: F1 is the real-time tension value of the pull rope 16, m is the simulated mass of the electric resistance source, f is the system resistance, dir is -1 when the pull rope 16 is pulled out and +1 when the pull rope 16 is recovered. The pull rope 16 is judged to be pulled out or recovered based on the calculated speed direction at the previous moment. The simulated mass m is input by the user on the touch screen controller 15.

[0036] Since the seated leg curling and extension machine of this embodiment has only one fixed pulley 18 wound between the winding wheel 13 and the curling and extension operating part 102, in practice the system resistance f is very small and can be ignored, and does not affect the body sensation.

[0037] In step S3, the initial velocity V0 at the beginning of the movement is 0, and the acceleration a is integrated for 0.001 seconds to obtain the real-time velocity magnitude and direction. According to the formula: V2=V0+a*0.001, in the interval of 0 to 0.001 seconds, the terminal velocity V2 (meters per second) is equal to the acceleration a*0.001 seconds+0 at this time; in the next interval of 0.001 to 0.002 seconds, the terminal velocity is equal to the terminal velocity of the previous interval plus the acceleration of the second interval*0.001 seconds; and so on for the next interval; in this way, the velocity magnitude and direction of any time interval (with 0.001 seconds as interval) during the movement process can be obtained with the start time of the movement as 0.

[0038] Alternatively, numerical integration can be used for approximate calculation. Taking the trapezoidal rule as an example, the time interval [0, t] is divided into n small intervals [t i-1 , t i ], i=1,2,3…,n; length of small interval△t i =t i -t i-1 , then in each small interval, the acceleration is approximately considered to change linearly, so the formula for the velocity v(t) at time t is as follows: ; Where: a(t i-1 ) is t i-1 The acceleration at a moment, a(t i ) is t i The acceleration of time.

[0039] In step S4, the speed and direction of the servo rotary motor 11 are calculated based on the required speed, the diameter of the winding wheel 13 and the transmission ratio of the reducer, and the electric resistance is output at the speed. Specifically, the speed n of the servo rotary motor 11 in any time interval can be calculated using the following formula, and the servo driver 14 controls the servo rotary motor 11 to continuously change the speed and direction according to the calculation result at a period of 0.001 seconds.

[0040] ; Wherein, n(t) is the motor speed at time t, v(t) is the speed of the pull rope 16 at time t (also the linear speed of the winding wheel 13), i is the transmission ratio, and r is the radius of the winding wheel 13.

[0041] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention shall be defined by the attached claims and their equivalents.

Claims

1. An electric resistance control method for a strength training device, characterized in that: The specific steps include: S1. Using a force sensor to obtain a real-time pulling force value of the pull rope on the electric resistance source, the pull rope serves as a force transmission component between the electric resistance source and the training operation part; S2, based on the real-time tension value of step S1 and the first formula, calculate the required acceleration a of the pull rope under the real-time tension value; The first formula is a=(F1-m×g+dir×f) / m, where: F1 is the real-time tension value of the pull rope, m is the simulated mass of the electric resistance source, f is the system resistance, dir is -1 when the pull rope is pulled out and +1 when the pull rope is retracted; S3, based on the initial velocity of zero and the acceleration that should have occurred at the historical moment, the magnitude and direction of the velocity of the rope at the current moment are calculated; S4, converting the required speed in step S3 to obtain the current operating parameters of the electric resistance source and outputting the electric resistance according to the operating parameters; The electric resistance source has a self-locking force.

2. The electric resistance control method of the strength training apparatus according to claim 1, characterized in that: The force sensor in step S1 is installed in the transmission path of the pull rope.

3. The electric resistance control method of the strength training apparatus according to claim 2, characterized in that: A fixed pulley is provided in the transmission path of the pull rope, and the force sensor is circular and coaxially mounted on the end of the central axis of the fixed pulley.

4. The electric resistance control method of the strength training apparatus according to claim 3, characterized in that: The type of the force sensor is a pressure sensor.

5. The electric resistance control method of the strength training apparatus according to claim 3, characterized in that: The real-time tension value F1 of step S1 and the force value F0 measured by the force sensor satisfy the following relationship: F0=2F1×CosA; wherein CosA is the cosine value of the angle A between the resultant force line of the force sensor and the pull rope at the fixed pulley.

6. The electric resistance control method of the strength training apparatus according to claim 1, characterized in that: The electric resistance source is a speed-controllable rotary motion device or a linear motion device equipped with a servo system.

7. The electric resistance control method of the strength training apparatus according to claim 6, characterized in that: The electric resistance source includes an electric cylinder equipped with a servo system, a linear motor and a rotary motor.

8. The electric resistance control method of the strength training apparatus according to claim 1, characterized in that: The electric resistance source adopts a combination of a servo rotary motor and a self-locking reducer, and a winding wheel is provided on the output shaft of the self-locking reducer. One end of the pull rope is wound on the winding wheel. The conversion method of step S4 is: based on the expected speed, the diameter of the winding wheel and the transmission ratio of the self-locking reducer, the speed and direction of the servo rotary motor are calculated.

9. The electric resistance control method of the strength training apparatus according to claim 8, characterized in that: The superposition calculation adopts numerical integration approximation calculation, and the formula is: ； Where: a(t i-1 ) is t i-1 The acceleration at a moment, a(t i ) is t i The acceleration of time.

10. The electric resistance system of the strength training apparatus according to claim 8, characterized in that: The self-locking reducer is a worm gear reducer.

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