Control device and control method for a strength training apparatus

Abstract

The control device and control method of the strength training apparatus of the present application can accurately acquire external force to control the speed of the permanent magnet motor without external force sensor. The control device of the strength training apparatus comprises: a rotary encoder for measuring the rotation angle of the permanent magnet motor providing electronic weight; a current sensor for measuring the current of the motor; an inverter for driving the permanent magnet motor; a current controller for generating a drive control signal output to the inverter according to the position detection signal, the sampled current and the given current value; a speed controller for generating the given current value and outputting it to the current controller according to the current rotation speed and the target rotation speed; and a mass tension simulator for generating the target rotation speed and outputting it to the speed controller based on the virtual mass setting value, the training tension setting value, the current rotation speed and the current tension value of the strength output input structure, the current rotation speed being acquired based on the position detection signal, and the current tension value being acquired from the sampled current through a specified operation.

Description

Technical Field

[0001] This invention relates to the field of fitness equipment technology, and in particular to an electronic weighted strength training machine capable of providing strength training functions, as well as its control device and control method. Background Technology

[0002] In recent years, home fitness equipment has seen significant development, with a variety of intelligent home fitness equipment with comprehensive functions hitting the market. These include fitness equipment that uses a smart home bicycle for aerobic exercise, fitness equipment that uses a smart home fitness mirror for aerobic exercise, and new types of intelligent home strength training equipment that use motor-driven resistance (i.e., electronic weights) instead of the traditional weight blocks found in strength training equipment.

[0003] Electronic weight training equipment uses electronic weights instead of physical weights, and provides resistance by controlling a motor to generate magnetic force. The user resists the resistance generated by the motor, pulling outwards through a cable connected to the motor, simulating the fitness method of traditional resistance bands that use physical weights. Summary of the Invention

[0004] The new type of resistance fitness equipment uses a motor as the resistance source, replacing traditional resistance sources such as weights, air resistance, eddy current resistance, and water resistance. Because the motor is the resistance source, if it simply outputs a constant resistance, the user experience may be significantly different from that of various traditional resistance sources. The most direct difference is the inertia.

[0005] Specifically, for weight training devices, the magnitude of inertia is related to the mass of the selected weights. A 5kg training weight results in a 5kg inertial mass, and a 20kg training weight results in a 20kg inertial mass. For wind resistance and magnetic resistance, the inertia of the flywheel can be felt; for water resistance, the mass or inertia of the water can be felt (depending on whether the water is moving linearly or rotationally). However, for resistance training devices using a motor as the resistance source, if resistance is output solely based on constant torque without interference, the user can only feel the inertia of the motor rotor and the corresponding transmission mechanism. This inertia is generally a constant value, but resistance training devices typically output resistance ranging from 0-50kg. Therefore, the mismatch between inertia and output force is a significant drawback of this system.

[0006] To address the aforementioned technical problems, Chinese patent application CN109890467A discloses a mass simulation method capable of reflecting the behavior of a weighing machine with counterweights. Specifically, it obtains the tension T using an external tension sensor, force sensor, or by measuring spring deformation, and then uses a method similar to v... new =v old +T / m 虚拟配重The target speed of the motor can be obtained by using a formula such as *Δt.

[0007] However, in the method disclosed in patent application CN109890467A, the sampling of tensile force T mainly employs elastic elements with displacement monitoring, strain gauges, rod-type pressure measuring elements, and weight sensors. These measurement methods are often structurally complex, and more critically, their measurement accuracy and frequency are not very high, leading to problems such as sampling lag, low accuracy, and high noise in tensile force T. This results in V new Its instability makes it unable to meet actual usage needs.

[0008] Therefore, the present invention provides a control device and control method for strength training equipment, which can accurately acquire external force to control the speed of the motor without the need for an external force sensor.

[0009] Furthermore, the present invention provides a control device and control method for a strength training device, which can provide a training mode that simulates any inertia and training tension value.

[0010] Technical means to solve the problem

[0011] To address the aforementioned problems, the present invention provides a control device for a strength training apparatus, wherein the strength training apparatus includes a permanent magnet motor that provides electronic counterweights for strength training, and a force output / input structure coupled to the rotor of the permanent magnet motor. The control device includes: a rotary encoder for measuring the rotation angle of the permanent magnet motor; a current sensor for measuring the current of the motor; an inverter for driving the permanent magnet motor; and a current controller that generates a drive control signal output to the inverter based on a position detection signal from the rotary encoder, a sampled current from the current sensor, and a given current value from an external source. A speed controller generates a given current value based on the current rotational speed of the permanent magnet motor and a given target rotational speed, and outputs the given current value to the current controller; and a mass-tension simulator generates the target rotational speed based on a virtual mass setting value from a user or host computer, a training tension setting value, the current rotational speed of the permanent magnet motor, and the current tension value of the force output input structure, and outputs the target rotational speed to the speed controller, wherein the current rotational speed is obtained based on the position detection signal of the rotary encoder, and the current tension value is obtained from the sampled current of the current sensor through a prescribed calculation.

[0012] Preferably, the current tension value is obtained by taking the current rotation speed constant for a specified first time period and performing the specified calculations from the sampled current of the current sensor during that specified first time period.

[0013] Preferably, the mass tension simulator is based on the formula v2=(T–F)*Δt2 / m 虚拟配重+v, calculate the target rotational speed after a specified second time, where v2 represents the target rotational speed, T represents the current tension value, m virtual counterweight represents the virtual mass setting value, F represents the training tension setting value, Δt2 represents the specified second time, and v represents the current rotational speed; the control device controls the rotational speed of the motor within the specified second time Δt2 to make it reach the target rotor speed v2.

[0014] Preferably, the permanent magnet motor is a three-phase permanent magnet synchronous motor. The current sensor measures at least two phase current signals of the three-phase permanent magnet synchronous motor. The inverter is a three-phase inverter circuit. The given current value is a given Q-axis current value. The drive control signal is an SVPWM signal. The system also includes a current converter, which converts the three-phase current signals into D-axis current values ​​and Q-axis current values ​​based on the at least two phase current signals and the position detection signal from the rotary encoder. The current tension value is obtained based on the Q-axis current value.

[0015] Preferably, the current tension value is obtained by keeping the current rotational speed constant within the specified first time period, acquiring the Q-axis current value Iq multiple times, and filtering and averaging the acquired Q-axis current values ​​Iq to obtain the average value Iq of the Q-axis current value, and then calculating the average value Iq based on the average value Iq.

[0016] Preferably, the first specified time is greater than 1 ms and less than 10 ms, and the second specified time is greater than 0.5 ms and less than 5 ms.

[0017] Furthermore, this invention provides a control method for a strength training device, wherein the strength training device includes a permanent magnet motor providing electronic counterweights for strength training, a force output / input structure coupled to the rotor of the permanent magnet motor, and a control device for the strength training device as described above. The control method includes: a current tension value acquisition step, which acquires the current tension value of the force output / input structure from the sampled current of the current sensor through a predetermined calculation; a target speed generation step, which generates a target speed of the permanent magnet motor based on a virtual mass setting value from a user or host computer, a training tension setting value, the current speed of the permanent magnet motor, and the current tension value acquired in the current tension value acquisition step; and a motor speed control step, which controls the permanent magnet motor to achieve the target speed through the speed controller, the current controller, and the inverter based on the target speed, the position detection signal of the rotary encoder, and the sampled current of the current sensor, and repeatedly performs the current tension value acquisition step, the target speed generation step, and the motor speed control step, so that the user can use the strength training device to perform strength training according to a set training mode.

[0018] Preferably, in the current tension value acquisition step, the current rotational speed is kept constant for a predetermined first time period, and the current tension value is acquired from the sampled current of the current sensor through the predetermined calculation within the predetermined first time period.

[0019] Preferably, in the target rotational speed generation step, the formula v2=(T–F)*Δt2 / m is used. 虚拟配重 +v, calculate the target rotational speed after a specified second time, where v2 represents the target rotational speed, T represents the current tension value, m virtual counterweight represents the virtual mass setting value, F represents the training tension setting value, Δt2 represents the specified second time, and v represents the current rotational speed; the motor speed control step controls the rotational speed of the motor within the specified second time Δt2 to make it reach the target rotor speed v2.

[0020] Preferably, the permanent magnet motor is a three-phase permanent magnet synchronous motor. The current sensor measures at least two phase current signals of the three-phase permanent magnet synchronous motor. The inverter is a three-phase inverter circuit. The given current value is a given Q-axis current value. The drive control signal is an SVPWM signal. The system also includes a current conversion step, which converts the at least two phase current signals into D-axis current values ​​and Q-axis current values ​​based on the at least two phase current signals and the position detection signal from the rotary encoder. The current tension value is obtained based on the Q-axis current value.

[0021] Preferably, the current tension value is obtained by keeping the current rotational speed constant within the specified first time period, acquiring the Q-axis current value Iq multiple times, and then filtering and averaging the acquired Q-axis current values ​​Iq to obtain the average value Iq of the Q-axis current value. 平均 Based on Iq 平均 What I'm asking for.

[0022] Preferably, the first specified time is greater than 1 ms and less than 10 ms, and the second specified time is greater than 0.5 ms and less than 5 ms.

[0023] Beneficial effects

[0024] The control device and method of the strength training equipment of the present invention can obtain the current speed of the motor based on the position detection signal of the rotary encoder, and obtain the current tension value based on the current current value of the motor. A target speed of the motor is generated based on a given mass-tension model, and the motor is controlled by a speed controller, a current controller, and an inverter to make its speed reach the target speed. In this way, external force can be accurately obtained to control the motor speed without the need for an external force sensor. Furthermore, the strength training equipment can simulate the training experience under any virtual mass setting and / or training tension setting.

[0025] Furthermore, since this invention does not employ sensors such as strain gauges, rod-type pressure measuring elements, or weight sensors that cause sampling lag in external forces, but instead obtains the current tension value based on the current current value of the motor, it can greatly improve the response speed and accuracy of motor speed control compared to existing technologies, thereby enhancing the user experience of strength training. Attached Figure Description

[0026] Figure 1 This is a diagram illustrating an example of the basic structure that provides strength training functions in an electronic weighted strength training device.

[0027] Figure 2 This is a block diagram illustrating the structure of the control device for the strength training apparatus of the present invention.

[0028] Figure 3 This is a circuit diagram illustrating the circuit structure of a motor driver according to one embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram representing two mechanical models of strength training.

[0030] Figure 5 This is a flowchart illustrating the control method of the strength training device of the present invention.

[0031] Figure 6 This is a schematic curve representing the change in motor speed in the control method of the present invention.

[0032] Figure 7 This is a flowchart showing how to calculate the tension value by repeatedly obtaining the Q-axis current value. Detailed Implementation

[0033] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0034] (Basic structure of electronic weight-based strength training equipment)

[0035] Electronic weight training equipment uses electronic weights instead of physical weights, and provides resistance by controlling a motor to generate magnetic force. The user resists the resistance generated by the motor, pulling outwards through a cable connected to the motor, simulating the fitness method of traditional resistance bands that use physical weights.

[0036] In one embodiment of the present invention, the basic structure of the electronic weight-type strength training device that provides strength training function can be: Figure 1 The structure shown.

[0037] Specifically, Figure 1 This is a diagram illustrating an example of the basic structure providing strength training functions in an electronic weight-based strength training device according to one embodiment. (See diagram for example.)Figure 1 As shown, the strength training equipment includes two motors 20 serving as resistance sources or electronic counterweights, two winches 21 fixed to the rotors of each motor for winding ropes, two ropes 22 each with one end fixed to the respective winch, two pulley systems including a first fixed pulley 23, a second fixed pulley 24, a third pulley 25, and a fourth pulley 26, two swing arms 30 respectively located on the left and right sides, and two training handles 31 respectively connected to the other ends of the two ropes. The rope 22 passes through the first fixed pulley 23, its direction changes to upward along the side of the machine, then passes through the second fixed pulley 24 at the top, adjusting its direction downward along the guide rail, and then passes through the third pulley 25 and the fourth pulley 26 into the swing arm 30. The rope 22 passes through the wrist joint pulley (not shown) of the swing arm 30 and exits, fixed to the training handle 31.

[0038] When the motor driver drives the motor 20, causing the winch 21 to rotate in the opposite direction to the pull rope 22, a force opposing the motor resistance is generated. When the pulling force is greater than the motor resistance, it's like pulling up a physical weight. Figure 1 The training handle 31 is pulled outward by a pulling force counteracting the force of equal weight generated by the motor 20 connected via the rope 21. When the pulling force is less than the motor resistance, the motor 20 rotates, causing the winch 21 to wind and retract the rope 22, equivalent to the weight falling back, and the training handle 31 is pulled inward. It should be noted that the motor resistance has a different nature from traditional resistance, such as friction. The direction of traditional resistance is opposite to the direction of motion, while the direction of motor resistance is a definite direction, which can be the same as the direction of motion, such as when the winch 21 winds and retracts the rope 22. The nature of the motor resistance is more similar to the counterweight in traditional strength training equipment. Here, the winch 21, the rope 22, and the pulley group including the first fixed pulley 23, the second fixed pulley 24, the third pulley 25, and the fourth pulley 26 constitute the transmission mechanism, and the rope 22 and the training handle 31 constitute the force input and output structure.

[0039] Here, two winches 21 for winding the rope are fixed to the rotors of each motor 20. The rope 22 is connected to the training handle 31 via a pulley system including a first fixed pulley 23, a second fixed pulley 24, a third pulley 25, and a fourth pulley 26. Instead of using a high-reduction-ratio transmission structure such as a gear set, the resistance when pulling the rope is significantly reduced, achieving high overall transmission efficiency. This allows for smooth strength training in various modes, including isokinetic and constant-speed movements. Furthermore, the use of two independently controllable motors 20 and two sets of rope pulley mechanisms connected to the rotors of each motor allows for independent resistance generation on the two training handles 31 extending from the two swing arms 30 on the left and right sides, greatly increasing the freedom of strength training.

[0040] However, the basic structure providing strength training functionality is not limited to the structure described above. Any electronic weight-type strength training device with a transmission structure possessing low transmission resistance can be used to implement this invention. Specifically, as long as it has a motor capable of generating resistance and a force output / input structure coupled to the motor's rotor via a transmission structure with a total transmission efficiency greater than or equal to 85%, allowing the user to apply force or perform work on the motor through this force output / input structure, and to receive force or work from the motor on the user through this force output / input structure, other structures can be used. For example, a mechanism with a winch, ropes, and pulleys can be used, but the number and configuration of the ropes and pulleys are not limited. Figure 1 The method shown, and it is also possible to not have Figure 1 The swing arm 30 in the original design can be replaced with other structures, such as a slider. Alternatively, a linkage structure can be used instead of a winch rope structure. As for the transmission structure, a gear transmission mechanism can also be used as long as the overall transmission efficiency is high.

[0041] As the motor generating resistance or electronic weight, a flat motor, as described in Chinese invention patent application number 202210461292.3, can be used. This flat motor has a multi-pole structure, enabling it to rotate at a lower speed and output a larger torque. Therefore, the low speed and high torque required by strength training equipment can be met without using a large reduction ratio transmission structure such as a gear set. Of course, the motor generating motor resistance or electronic weight is not limited to the aforementioned flat motor; motors with other structures and shapes can also be used.

[0042] (Control device for strength training equipment)

[0043] The present invention provides a control device for a strength training apparatus. As described above, the strength training apparatus includes a permanent magnet motor that provides electronic counterweights for strength training, and a force output input structure coupled to the rotor of the permanent magnet motor.

[0044] Figure 2 This is a block diagram illustrating the structure of the control device for the strength training apparatus of the present invention.

[0045] like Figure 2 As shown, the control device of the present invention includes: a rotary encoder 11 for measuring the rotation angle of a permanent magnet motor 10; a current sensor 12 for measuring the current of the motor; an inverter 13 for driving the permanent magnet motor; a current controller (also called a current control loop) 14, which generates a drive control signal output to the inverter 13 based on the position detection signal from the rotary encoder 11, the sampled current from the current sensor 12, and a given current value from an external source; a speed controller (also called a speed control loop) 15, which generates the given current value based on the current speed of the permanent magnet motor and a given target speed, and outputs the given current value to the current controller 14; and a mass-tension simulator 16, which generates the target speed based on a virtual mass setting value from a user or host computer, a training tension setting value, the current speed of the permanent magnet motor, and the current tension value of the force output input structure, and outputs the target speed to the speed controller 15. As detailed below, the current speed is obtained based on the position detection signal of the rotary encoder 11, and the current tension value is obtained from the sampled current of the current sensor 12 through a predetermined calculation.

[0046] use Figure 2 The control device shown can obtain the current motor speed based on the position detection signal of the rotary encoder and obtain the current tension value based on the current current value of the motor. A mass tension simulator generates the target motor speed based on a given mass tension model, and the motor speed is controlled by a speed controller, current controller, and inverter to achieve this target speed. In this way, external force can be accurately acquired to control the motor speed without the need for an external force sensor. Furthermore, it enables strength training equipment to simulate the training experience under any virtual mass setting and / or training tension setting.

[0047] As will be explained later, preferably, the current tension value is obtained by performing the specified calculation on the sampled current of the current sensor within a specified first time period while keeping the current rotational speed constant.

[0048] Preferably, the mass tension simulator is based on the formula v2=(T–F)*Δt2 / m 虚拟配重 +v, calculate the target rotational speed after the specified second time interval, where v2 represents the target rotational speed, T represents the current tension value, and m 虚拟配重 The virtual mass setting value is represented by F, the training tension setting value is represented by Δt2, the specified second time is represented by v, and the current rotational speed is represented by v. The control device controls the rotational speed of the motor within the specified second time Δt2 to make it reach the target rotational speed v2.

[0049] Preferably, the permanent magnet motor is a three-phase permanent magnet synchronous motor, the current sensor measures the three-phase current signal of the three-phase permanent magnet synchronous motor, the inverter is a three-phase inverter, the given current value is a given Q-axis current value, and the drive control signal is an SVPWM signal. The control device also includes a current converter, which converts the three-phase current signal into D-axis current value and Q-axis current value based on the three-phase current signal and the position detection signal from the rotary encoder, and the current tension value is obtained based on the Q-axis current value.

[0050] As will be explained later, preferably, the current tension value is obtained by keeping the current rotational speed constant within the specified first time period, acquiring the Q-axis current value Iq multiple times, and filtering and averaging the acquired Q-axis current values ​​Iq to obtain the average value Iq of the Q-axis current value. 平均 Based on Iq 平均 What I'm asking for.

[0051] Preferably, the first specified time is greater than 1 ms and less than 10 ms, and the second specified time is greater than 0.5 ms and less than 5 ms.

[0052] The control device of the strength training equipment in this embodiment will be described in more detail below, taking the use of a three-phase AC permanent magnet synchronous motor as an example.

[0053] With the technological advancements in three-phase AC permanent magnet synchronous motors (3PH PMSMs), superior magnetic circuit simulation techniques and electromagnetic materials have emerged. Through meticulous design, the 3PH PMSM exhibits extremely low torque ripple (less than 0.4% in one embodiment). Under Id=0 control, the input Q-axis current Iq of the 3PH PMSM is precisely linearly proportional to the output torque M. If the torque ripple is large, for example, 2%, then for a constant input Iq, M will fluctuate by 2%. If the target M is 10 Nm, then the actual M will vary between 9.9 Nm and 10.1 Nm. If a winch with a radius R=4.5 cm is used, then the motor output force F will vary between 220 N and 224.4 N. This 4.4 N force variation will negatively impact the user's handling experience and will also affect the accuracy of tension measurement, as described below.

[0054] like Figure 2 As shown, in order for the driver to drive the 3PH PMSM, the control device has two control loops: a current control loop and a speed control loop.

[0055] A high-precision rotary encoder (which can be a photoelectric encoder, magnetic encoder, rotary transformer, etc.) is mounted on the motor shaft. In this embodiment, a magnetic encoder is used to reduce size and control costs. The rotary encoder can acquire the angle of the motor shaft in real time, with an accuracy that can easily reach 4000 p / r (1 / 4000th of a revolution, 0.09 degrees), and its real-time performance is very high, with an output frequency that can easily reach above 2kHz. The Park transformation and SVPWM in the current control loop both require calculating the motor electrical angle θE based on the absolute position P of the motor shaft output by the encoder and the number of motor stages.

[0056] The inputs to the current controller (current control loop) are the given D-axis power Id and the given Q-axis power Iq. Id and Iq need to be transformed into target three-phase currents IU, IV, and IW through Park and Clark transformations. The system inputs specific voltages to the three phase coils of the motor via SVPWM, and, acting as a current sensor, samples the actual three-phase currents IU', IV', and IW' through at least one sampling resistor in a time-division manner. The actual three-phase currents IU', IV', and IW' are then transformed through Park and quadrature transformations to obtain the actual Id' and Iq', forming the sampling feedback of the current control loop. With the current control loop feedback, the voltages input to the three-phase coils by SVPWM can be adjusted using a PI (Proportional-Integral) control algorithm, thereby controlling Id' and Iq' to quickly and accurately approximate Id and Iq.

[0057] The input to the speed controller (speed control loop) is the target speed v. Since the encoder can provide real-time feedback on the absolute position P of the motor shaft, the actual speed v' = (P2 - P1) / Δt can be calculated by continuously acquiring data at small intervals Δt (e.g., 0.3 ms). v' serves as speed feedback, and the magnitude of Iq can be adjusted using a PI (proportional-integral) control algorithm to change the magnitude of the motor's output torque. Therefore, v' can be controlled to quickly and accurately approximate v.

[0058] Figure 3 This is a circuit diagram illustrating the circuit structure of a motor driver according to one embodiment of the present invention.

[0059] like Figure 3 As shown, the permanent magnet motor in this embodiment is a three-phase permanent magnet synchronous motor. The motor driver includes an MCU controller that can realize the functions of current controller and speed controller, and a three-phase inverter circuit composed of 6 switching transistors, with a diode connected in reverse parallel to each switching transistor.

[0060] The following explains in more detail how to utilize... Figure 3 The circuit structure shown is used for resistance control of the motor.

[0061] Six switching transistors 101-106 form a three-phase inverter circuit. The control logic is determined by six PWM control signals 114 output by the MCU controller 112. These six PWM control signals are amplified and isolated by the drive circuit 115 to control the IGBT switching transistors. 101 and 102 serve as inverter switches for the U-phase 107, 103 and 104 for the V-phase 108, and 105 and 106 for the W-phase 109. The control signal output for the three-phase permanent magnet synchronous motor 110 is achieved through inverter modulation algorithms such as SVPWM or SPWM.

[0062] 116, 117, and 118 are the current sampling resistors for the three-phase switching transistors. According to Ohm's law U = R * I, the current 119 flowing through the three-phase switching transistors and sampling resistors can be calculated by collecting the voltage values ​​of the current sampling resistors. 101 and 102 cannot be simultaneously in the open state, 103 and 104 cannot be simultaneously in the open state, and 105 and 106 cannot be simultaneously in the open state; otherwise, a short circuit will occur. Based on this principle, knowing the current values ​​flowing through the current sampling resistors, the output currents 107, 108, and 109 can be obtained.

[0063] The three-phase current sampling method for motors is not limited to the above-mentioned forms. High-level sampling can also be used, where at least two resistors are connected in series with two of the motor's three-phase power lines to sample the current. Furthermore, there are various options for the sampling sensors, including but not limited to: Hall effect current sampling devices, current transformers, etc.

[0064] In addition, to reduce costs, only two phase currents can be sampled, and the third phase current can be calculated by the sum of the three phase currents being zero.

[0065] The three-phase permanent magnet synchronous motor 110 provides photoelectric encoders, magnetic rotary encoders, Hall sensors, etc. The MCU controller 112 can obtain feedback information such as the position and speed of the motor by connecting these sensors.

[0066] The MCU controller 112 collects the bus voltage 121 of the inverter circuit. When necessary, it controls the IGBT switch 111 to form a discharge circuit with the braking resistor 113 and the capacitor 122 to achieve the discharge function, thereby preventing the bus voltage from being too high and damaging the components.

[0067] The above explains how to achieve precise motor speed control of the 3PH PMSM through the current control loop and speed control loop. It also demonstrates that in the torque control loop of the 3PH PMSM, Iq and torque M are precisely linearly proportional. Based on this, we can achieve torque monitoring of the 3PH PMSM without the need for external force (torque) / weighing / spring or other external force (torque) monitoring sensors. This will be explained in detail below.

[0068] First, let me explain the mass tensile simulator.

[0069] Figure 4 These are schematic diagrams representing two mechanical models of strength training. The mechanical model represented by traditional weight machines is [A]. The model represented by digital strength training equipment using a motor as the resistance source is [B]. Because the moment of inertia of the motor rotor is constant and cannot change with the training force setting F, the experience will be significantly different from model [A].

[0070] By using a mass tension simulator, not only can model [B] be used to simulate the feeling of model [A], but model B can also be used to simulate the feeling of any m and F.

[0071] Specifically, in model [A], for a counterweight of mass m, when subjected to an upward pulling force T and a gravitational force mg, where g is the acceleration due to gravity (taking upward as the positive direction), the counterweight should move with an acceleration a = (T - mg) / m. Therefore, within a very small time slice Δt (e.g., ranging from 1 to 10 ms), the change in velocity of the counterweight is Δv = a * Δt. After time slice Δt, the new velocity v' is v' = v + Δv. If we know T, we can use the known conditions m, Δt, and the velocity v from the previous time slice to obtain the velocity v' after time slice Δt. After the next Δt, the new v' can be calculated using the same method.

[0072] Similarly, in model [B], the formula v'=(T–F)*Δt / m can be used. 虚拟配重 +v, calculate the velocity v' after Δt, where T represents the current tension value, m 虚拟配重 This represents the virtual mass setting value, and F represents the training pull setting value.

[0073] If there is an object at this moment, regardless of its mass and the friction it is subjected to, as long as it can move according to the above algorithm when subjected to an external force T, a person will feel that the object has a mass of m.

[0074] Below is a brief explanation of an example of the motion patterns that can be achieved using model [B].

[0075] (1) Isotonic motion

[0076] Isotonic motion refers to a state in which the force input and output mechanisms maintain a relatively constant tension value throughout strength training. This is described by the formula v'=(T–F)*Δt / m. 虚拟配重 In +v, T and F are approximately equal, while m 虚拟配重 This refers to cases where m is taken as a very small value. In practical control, m can be... 虚拟配重Set it to a very small non-zero value. According to the formula above, as long as TF≠0, it is subject to the denominator m. 虚拟配重 A very small influence can cause a very drastic change in v2. This is the feeling of low inertia, which can be compared to stretching a rubber band.

[0077] (2) Constant velocity motion

[0078] Isokinetic motion refers to the process during strength training where the force input and output mechanisms maintain approximately a constant speed. This is defined in the formula v'=(T–F)*Δt / m. 虚拟配重 In +v, m 虚拟配重 The case where m takes a very large value. 虚拟配重 When it is infinite, (T–F)*Δt / m 虚拟配重 As it approaches zero, v' = v.

[0079] Thanks to the high-speed response capability of the driver, m can be changed at any point in time. 虚拟配重 And F, thus enabling the fulfillment of specific training requirements. For example:

[0080] (3) Each time the user pulls the rope back and forth, m increases or decreases. 虚拟配重 and F 训练设定

[0081] (4) m of centripetal and centrifugal motion 虚拟配重 Not equal to F

[0082] Training emphasizes eccentric contraction, meaning the eccentric contraction load is greater than the concentric contraction load, primarily focusing on training muscle strength and endurance. Conversely, if the concentric contraction load is greater than the eccentric contraction load, the focus is on training muscle response and explosive power.

[0083] (5) The m values ​​differ at different joint angles. 虚拟配重 and F

[0084] Since the human muscle and the two associated bones form a triangular structure, the tension generated at the end of the bone is different when the muscle exerts force at different joint angles. Therefore, in order to ensure that the muscle reaches a fixed proportion of its maximum capacity throughout the entire contraction process, we can set a curve for the F-related joint angle, so that there is an appropriate F output when the joint reaches different angles.

[0085] (6) Rowing mode

[0086] In rowing mode, m 虚拟配重 The mass of the boat and the people can be set, and F can be set as the resistance force f acting on the boat. 船Because the resistance experienced by the ship is affected by factors such as ship speed, water environment (wind, waves, laminar and turbulent flow, etc.), and hull shape, F is a real-time changing value. Generally, the model can be simplified to let F = f 船 =kv, or F=f 船 =kv 2 (When the boat is fast enough).

[0087] The following explains how to perform tension monitoring without setting up an external force measuring mechanism.

[0088] In the method disclosed in patent application CN109890467A, the sampling of tensile force T mainly employs elastic elements with displacement monitoring, strain gauges, rod-type pressure measuring elements, and weight sensors. These measurement methods are often structurally complex, and more critically, their measurement accuracy and frequency are not very high, leading to problems such as sampling lag, low accuracy, and high noise in tensile force T. This results in V... new Its instability makes it unable to meet actual usage needs.

[0089] Therefore, the present invention provides a control device and control method for strength training equipment, which can accurately obtain the external force T to control the speed of the motor without the need for an external force sensor.

[0090] The control device of this invention has a high-precision encoder to monitor the position P of the motor rotor. It can calculate the rotor speed v = (P2 - P1) / Δt by monitoring P1 and P2 twice with a time interval of Δt. Alternatively, it can calculate the rotor speed a = ((P3 - P2) / Δt - (P2 - P1) / Δt) / Δt = (P3 + P1 - 2P2) / Δt2 by monitoring P1, P2, and P3 three times with a time interval of Δt in each pair.

[0091] If, within a time period Δt1 (e.g., more than 1 ms), the acceleration a of the rotor structure is 0 and v is constant, then the sum of the radial external forces acting on the rotor structure at this time can be considered to be 0. The external forces acting on the rotor structure are mainly the electromagnetic force F (the force between the motor stator and rotor), the user's tension T (transmitted to the winch through rope tension), and the frictional force f. f can be considered sufficiently small to be negligible (in one embodiment, f is less than 0.1 N). Because a = 0, F = T (if f is not negligible, it can be approximated by measurement; the formula is F = T ± f, with the plus or minus sign depending on the direction of rotor motion). Since F is proportional to Iq, and Iq is obtained from feedback from the current loop PI automatic control system, it can be expressed by the formula F = k1 * Iq, then T = F = k1 * Iq. Therefore, as long as the rotor structure is controlled to move at a constant speed within Δt1, the user's tension T can be calculated from Iq. This eliminates the need for tension monitoring using an external force / weighing / elastic force structure.

[0092] The value of k1 can be determined, for example, as follows: When the motor input Iq = 1A, measure T with a force gauge. After changing Iq and measuring multiple times, obtain a table showing the correspondence between Iq and T. If the linearity is good, a linear function can be directly used for fitting. The specific k1 can be fixed or obtained from a table.

[0093] The specific implementation method for calculating the user's pulling force T based on Iq will be explained in detail in the description of the control method.

[0094] In the above embodiments of the present invention, the motor providing the electronic counterweight is a three-phase AC permanent magnet synchronous motor. However, the present invention is not limited to the above embodiments, and other motors may be used to provide the electronic counterweight.

[0095] (Control methods for strength training equipment)

[0096] This invention provides a control method for a strength training device, wherein the strength training device includes a permanent magnet motor that provides electronic weights for strength training, a force output / input structure coupled to the rotor of the permanent magnet motor, and... Figure 2 The control device shown.

[0097] Figure 5 This is a flowchart illustrating the control method of the strength training device of the present invention.

[0098] like Figure 5 As shown, a control method according to one embodiment of the present invention includes: a current tension value acquisition step S1, which acquires the current tension value of the force output input structure from the sampled current of the current sensor through a predetermined calculation; a target speed generation step S2, which generates a target speed of the permanent magnet motor based on a virtual mass setting value from the user or host computer, a training tension setting value, the current speed of the permanent magnet motor, and the current tension value acquired in the current tension value acquisition step; and a motor speed control step S3, which controls the permanent magnet motor to achieve the target speed through the speed controller, the current controller, and the inverter based on the target speed, the position detection signal of the rotary encoder, and the sampled current of the current sensor, and repeatedly performs the current tension value acquisition step S1, the target speed generation step S2, and the motor speed control step S3, so that the user can use the strength training equipment to perform strength training according to the set training mode.

[0099] use Figure 5The control method shown can obtain the current motor speed based on the position detection signal of the rotary encoder and obtain the current tension value based on the current current value of the motor. Then, a target motor speed is generated based on a given mass tension model, and the motor is controlled to achieve the target speed. By repeatedly executing steps S1 to S3, the movement speed based on a given mass tension model can be continuously responded to by the tension applied by the user. In this way, the strength training equipment can simulate the training experience under any virtual mass setting and / or training tension setting. Furthermore, it can accurately obtain external force to control the motor speed without the need for an external force sensor.

[0100] The following is about Figure 5 The control method described above will be further explained. Taking isotonic motion as an example, the above control method can control the motor speed to a training speed corresponding to the tension applied by the user during isotonic motion. One cycle of isotonic motion is 1 second to several seconds, which is a relatively long time period. Isotonic motion within such a long time period is achieved by continuously controlling the speed in millisecond-level time intervals. This speed control in millisecond-level time intervals constitutes one control cycle including steps S1 to S3.

[0101] In this invention, the current tension value is acquired and the speed is controlled within two consecutive time periods on the order of milliseconds, namely a specified first time Δt1 and a specified second time Δt2, respectively, to achieve tension detection and speed control.

[0102] Preferably, in the current tension value acquisition step S1, the current rotational speed is kept constant within a specified first time Δt1, and the current tension value is acquired from the sampling current of the current sensor through the specified calculation within the specified first time Δt1.

[0103] Preferably, in the target speed generation step S2, the formula v2=(T–F)*Δt2 / m is used. 虚拟配重 +v, calculate the target rotational speed after the specified second time Δt2, where v2 represents the target rotational speed, T represents the current tension value, and m 虚拟配重 The virtual mass setting value is represented by F, the training tension setting value is represented by v, and the current rotational speed is represented by v. The motor speed control step S3 controls the rotational speed of the motor within the specified second time Δt2 to make it reach the target rotor speed v2.

[0104] By repeatedly applying the control method described above, the motion speed based on a given mass tension model can be obtained by continuously responding to the tension applied by the user. This will be explained in detail below.

[0105] Figure 6This is a schematic curve representing the change in motor speed in the control method of the present invention. For example... Figure 6 As shown, during the first Δt1 time interval, the motor speed is maintained at v1. During this period, the current tension value is obtained based on the current motor current value, and the target motor speed v2 is obtained based on the current tension value. During the first Δt2 time interval, the motor speed is controlled to reach the target speed v2. Then, during the second Δt1 time interval, the motor speed is maintained at v2. During this period, the current tension value is obtained based on the current motor current value, and the target motor speed v3 is obtained based on the current tension value. During the second Δt2 time interval, the motor speed is controlled to reach the target speed v3. This same control is then performed to continuously respond to the tension applied by the user to obtain the motion speed based on a given mass tension model.

[0106] from Figure 6 As can be seen, the rotational speed of the motor rotor is not continuous; in fact, the motor rotor operates within a stepped curve. However, as long as Δt1 and Δt2 are sufficiently small, it can closely approximate a continuous curve. Of course, Δt1 and Δt2 also have lower limits, determined by the response speed of the rotary encoder, the operating frequency of the controller that controls the motor speed, etc. Preferably, the specified first time Δt1 is greater than 1 ms and less than 10 ms, and the specified second time Δt2 is greater than 0.5 ms and less than 5 ms. In this invention, since sensors such as strain gauges, rod-type pressure measuring elements, and weight sensors that cause sampling lag in the tension T are not used, and the current tension value is obtained based on the current current value of the motor, the response speed and accuracy of speed control can be greatly improved compared to existing technologies, thus enhancing the user experience for strength training.

[0107] Preferably, the permanent magnet motor is a three-phase permanent magnet synchronous motor, the current sensor measures the three-phase current signal of the three-phase permanent magnet synchronous motor, the inverter is a three-phase inverter, the given current value is a given Q-axis current value, the drive control signal is an SVPWM signal, and the control method further includes a current conversion step, which converts the three-phase current signal into D-axis current value and Q-axis current value based on the three-phase current signal and the position detection signal from the rotary encoder, and the current tension value is obtained based on the Q-axis current value.

[0108] Preferably, the current tension value is obtained by keeping the current rotational speed constant within the specified first time Δt1, acquiring the Q-axis current value Iq multiple times, and then filtering and averaging the acquired Q-axis current values ​​Iq to obtain the average value Iq of the Q-axis current value. 平均 Based on Iq 平均 What I'm asking for.

[0109] The following reference Figure 7 This document details an embodiment of determining the current tension value by repeatedly acquiring the Q-axis current value Iq within the first time interval Δt1.

[0110] Figure 7 This is a flowchart showing how to calculate the tension value by repeatedly obtaining the Q-axis current value.

[0111] like Figure 7 As shown, in step S11, timing begins for a predetermined Δt1, for example, 2ms. In step S12, the speed of the motor rotor is controlled to remain constant at v1. In step S13, the time Δt3 is waited for, which can be 1 / 5 to 1 / 10 of Δt1. In step S14, it is determined whether the time Δt1 has been reached. If not, proceed to step S15; if so, proceed to step S16. In step S15, the current Q-axis current value Iq is obtained and recorded in an array, then the process returns to step S12. This process is repeated multiple times from step S12 to step S15, allowing the Q-axis current value Iq to be obtained multiple times. In step S16, the multiple Iq values ​​stored in the array are filtered and averaged to obtain the final Iq. 平均 In step S17, via Iq 平均 Calculate the current tension value.

[0112] The average value Iq of the Q-axis current is obtained by acquiring the Q-axis current value Iq multiple times, and then filtering and averaging the acquired Q-axis current values ​​Iq. 平均 Based on Iq 平均 Calculating the current tension value, compared to calculating the current tension value based on a single Q-axis current value Iq, can improve the accuracy of the obtained current tension value and achieve more precise control of the motor speed.

Claims

1. A control device for a strength training machine, wherein, The strength training equipment includes a permanent magnet motor that provides electronic weights for strength training, and a force output / input structure coupled to the rotor of the permanent magnet motor. The control device of the strength training equipment is characterized by comprising: A rotary encoder for measuring the rotation angle of the permanent magnet motor; A current sensor for measuring the current of the permanent magnet motor; Inverter used to drive the permanent magnet motor; A current controller generates a drive control signal output to the inverter based on the position detection signal from the rotary encoder, the sampled current from the current sensor, and a given current value from an external source. A speed controller generates a given current value based on the current speed of the permanent magnet motor and a given target speed, and outputs the given current value to the current controller; and The mass-tension simulator generates the target rotational speed based on virtual mass settings from the user or host computer, training tension settings, the current rotational speed of the permanent magnet motor, and the current tension value of the force output input structure, and outputs the target rotational speed to the speed controller. The current rotational speed is obtained based on the position detection signal of the rotary encoder, and the current tension value is obtained from the sampled current of the current sensor through a prescribed calculation.

2. The control device for the strength training equipment as described in claim 1, characterized in that, The current tension value is obtained by performing a predetermined calculation on the sampled current from the current sensor within a predetermined first time period while keeping the current rotation speed constant.

3. The control device for the strength training equipment as described in claim 2, characterized in that, The mass tension simulator is based on the formula v2=(TF)*Δt2 / m 虚拟配重 +v, calculate the target rotational speed after the specified second time interval, where v2 represents the target rotational speed, T represents the current tension value, and m 虚拟配重 The virtual mass setting value is represented by F, the training tension setting value is represented by Δt2, the specified second time is represented by v, and the current rotational speed is represented by v. The control device controls the rotational speed of the permanent magnet motor to the target rotational speed v2 within the specified second time Δt2.

4. The control device for the strength training equipment as described in claim 2 or 3, characterized in that, The permanent magnet motor is a three-phase permanent magnet synchronous motor. The current sensor measures the current signals of at least two phases of the three-phase permanent magnet synchronous motor. The inverter is a three-phase inverter circuit. The given current value is the given Q-axis current value. The drive control signal is an SVPWM signal. It also includes a current converter that converts the at least two-phase current signals into D-axis and Q-axis current values ​​based on the at least two-phase current signals and the position detection signal from the rotary encoder. The current tension value is obtained based on the Q-axis current value.

5. The control device for the strength training equipment as described in claim 4, characterized in that, The current tension value is obtained by keeping the current rotational speed constant within the specified first time period, acquiring the Q-axis current value Iq multiple times, and then filtering and averaging the acquired Q-axis current values ​​Iq to obtain the average value Iq of the Q-axis current value. 平均 Based on Iq 平均 What I'm asking for.

6. The control device for the strength training equipment as described in claim 3, characterized in that, The first specified time is greater than 1ms and less than 10ms, and the second specified time is greater than 0.5ms and less than 5ms.

7. A method for controlling a strength training device, wherein, The strength training equipment includes a permanent magnet motor providing electronic weights for strength training, a force output / input structure coupled to the rotor of the permanent magnet motor, and a control device as described in claim 1, wherein the control method is characterized by comprising: The current tensile force value acquisition step involves obtaining the current tensile force value of the force output input structure from the sampled current of the current sensor through a prescribed calculation. The target rotational speed generation step generates the target rotational speed of the permanent magnet motor based on the virtual mass setting value from the user or host computer, the training tension setting value, the current rotational speed of the permanent magnet motor, and the current tension value obtained in the current tension value acquisition step; and The motor speed control step involves, based on the target speed, the position detection signal from the rotary encoder, and the sampled current from the current sensor, controlling the permanent magnet motor via the speed controller, the current controller, and the inverter to make its speed reach the target speed. By repeatedly performing the steps of obtaining the current tension value, generating the target speed, and controlling the motor speed, the user can use the strength training equipment to perform strength training according to the set training mode.

8. The control method for the strength training device as described in claim 7, characterized in that, In the step of obtaining the current tension value, the current rotational speed is kept constant for a specified first time period, and the current tension value is obtained from the sampled current of the current sensor through the specified calculation within the specified first time period.

9. The control method for the strength training device as described in claim 8, characterized in that, In the target rotational speed generation step, based on the formula v2=(TF)*Δt2 / m 虚拟配重 +v, calculate the target rotational speed after the specified second time interval, where v2 represents the target rotational speed, T represents the current tension value, and m 虚拟配重 The virtual mass setting value is represented by F, the training tension setting value is represented by Δt2, the specified second time is represented by v, and the current rotational speed is represented by v. The motor speed control step controls the speed of the permanent magnet motor to the target speed v2 within the specified second time Δt2.

10. The control method for the strength training device as described in claim 8 or 9, characterized in that, The permanent magnet motor is a three-phase permanent magnet synchronous motor. The current sensor measures the current signals of at least two phases of the three-phase permanent magnet synchronous motor. The inverter is a three-phase inverter circuit. The given current value is the given Q-axis current value. The drive control signal is an SVPWM signal. It also includes a current conversion step, which converts the at least two-phase current signals into D-axis current values ​​and Q-axis current values ​​based on the at least two-phase current signals and the position detection signal from the rotary encoder. The current tension value is obtained based on the Q-axis current value.

11. The control method for the strength training device as described in claim 10, characterized in that, The current tension value is obtained by keeping the current rotational speed constant within the specified first time period, acquiring the Q-axis current value Iq multiple times, and then filtering and averaging the acquired Q-axis current values ​​Iq to obtain the average value Iq of the Q-axis current value. 平均 Based on Iq 平均 What I'm asking for.

12. The control method for the strength training device as described in claim 9, characterized in that, The first specified time is greater than 1ms and less than 10ms, and the second specified time is greater than 0.5ms and less than 5ms.

Images