KR20010000018A - The control circuit and method for constant velocity of a treadmill - Google Patents

Abstract

PURPOSE: Constant speed running circuit of run sporting device corrects value changed with high frequency by sensing change on belt for real time, assures comfortable exercise by removing external fatigue and danger factor of athlete in using run sporting device, improves quality of various run sporting device, is import replacement effect by contributing localization of run sporting device. CONSTITUTION: The Constant speed running circuit of run sporting device comprises current detecting part(140) to transmit to error amplifier by detecting flowing electric current in rotor of electromotor to add(IR compensation) in input voltage of electromotor by amplifying and dividing voltage, after changing flowing electric current in rotor to voltage on falling rotational frequency of DC motor; error amplitude part(160) to transmit to compensating terminal of comparative amplitude part(190) by changing to voltage after amplifying current signal detected in current detecting part(140); oscillation part(180) to departure chopping wave as base frequency to control the electromotor; input part(170) to be input voltage to control the electromotor rotation; comparative amplitude part(190) to generate spherical wave to drive switching part(130) by comparing signal transmitted from input part(170) and error amplitude part(160) with chopping wave transmitted from the oscillation part(180); switching part(130) to intermittent-control power source(100) provided to the rotation in accordance with spherical wave signal of comparative amplitude part(190).

Description

The control circuit and method for constant velocity of a treadmill

The present invention relates to a constant speed control circuit and method for controlling the rotational speed of a running motor driven by a DC motor to be constantly maintained regardless of the exercise state of the exerciser.

The running exerciser is composed of two rollers installed at regular intervals, a belt spanning the rollers, and an electric motor that rotates by providing power to the rollers. At the lower end of the belt, a support of wood or similar material is mounted. In the exercise machine, when a person starts to exercise, the belt rotates at a set speed. According to the speed of the belt, the weight of the trainee impacts the belt and the support, and the impact causes friction that inhibits the rotation of the belt. This friction occurs when the foot of the athlete touches the belt and disappears when the foot is released. When the friction occurs, the rotational speed of the motor decreases, and when the friction disappears, the rotational speed returns to the original state. The subject becomes unstable and fatigue accumulates due to the change of the rotational speed.

In order to solve this problem, various methods have been proposed. First, there is a speed regulation circuit using SCR. This circuit controls the speed by the phase angle of the alternating current and the conduction angle of the SCR. However, since this control circuit performs control at half cycle time intervals of commercial power (60 Hz), it is difficult to perform uniform speed control due to poor trackability of change in weight and speed, that is, fast response speed (basically 8 ms to It is controlled by the cycle of 10ms. Second, the speed regulation circuit adopting the pulse width modulation (PWM) method. This circuit is used to compensate for the shortcomings of the control circuit using SCR. It is superior to the SCR method because it controls the conduction time based on the relatively high frequency, but the voltage drop applied to the motor under radically changing load conditions. It is difficult to keep the rotational speed constant because it cannot be prevented. This drop in voltage is due to the inductance component of the rotor of the motor. Third, there is a rotation speed control method using a ride meter. This method is a method using a ride meter for the purpose of detecting the rotational speed and to compensate for this, there is a problem such as economical and environmental malfunction, which is not preferable to adopt.

The object of the present invention in consideration of this point is that in the running exercise machine using a DC motor, the movement speed of the belt is kept constant in spite of the change of the condition (step, load, etc.) of the exerciser, so that the exercise in the natural and balanced posture of the exerciser is maintained. It is to provide a control circuit for adjusting the rotational speed of the DC motor to be maintained.

1 is a block diagram of a constant speed driving circuit of a running exercise machine according to an embodiment of the present invention,

2 is a circuit diagram of a constant speed traveling circuit of a running exercise machine according to an embodiment of the present invention,

3 is a detailed circuit diagram of a hybrid IC consisting of an input unit 170, an error amplifier 160, an oscillator 180, and a comparative amplifier 190 of the constant speed driving circuit of the running exercise machine according to an embodiment of the present invention, respectively. Indicates.

* Description of the symbols for the main parts of the drawings *

DESCRIPTION OF SYMBOLS 100 Power supply 110 Power supply part 115 Rectification part 120 Filter part 130 Switching part

140: current detector 150: overspeed detector 160: error amplifier 170: input 180: oscillator

190: Comparative amplification part

As mentioned above, the present invention relates to a method of constantly controlling the speed of a direct-current motor in which the load variation of the running motor is extreme.

The present invention detects the current flowing in the rotor of the DC motor driving the running motor and sends it to the error amplifier and the current amplifier 140, and amplifies the current signal detected by the current detector 140, the comparative amplifier 190 Error amplification unit 160 for converting and transmitting the voltage necessary for the transmission, oscillation unit 180 for oscillating a triangular wave, which is a fundamental frequency for controlling the motor, and an input unit 170 for receiving a voltage for controlling the rotation of the motor. And a comparison amplifier 190 for generating a square wave driving the switching unit 130 by comparing the signal transmitted from the input unit 170 and the error amplifier 160 with the triangular wave transmitted from the oscillator 180. The switching unit 130 intermittently controls the power supply 100 supplied to the motor according to the square wave signal of the comparison amplifier 190.

Referring to the schematic operation of the present invention having the configuration as described above are as follows.

The rotation speed of the DC motor is proportional to the magnitude of the voltage applied to the rotor. When the load increases, the rotation speed of the motor decreases and the current flowing to the motor increases, but the counter electromotive force decreases. This is caused by the resistance and inductance components of the rotor windings of the motor. Therefore, by monitoring the current flowing in the motor, it is possible to read the decrease in the rotational speed and determine the amount of feedback that can be reduced to the original rotational speed. A circuit using this principle is called an IR compensation circuit. This circuit acts in a direction to increase the voltage applied to the rotor as the current flowing through the rotor of the motor increases. This increased voltage increases the rotational speed of the rotor and eventually reduces the current. As a result, the running motor driving device having such a compensation circuit can guarantee a constant rotational speed even if the load fluctuates rapidly, thereby ensuring a comfortable movement of the exercised person.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. 1 is a block diagram showing a preferred embodiment of the constant speed control circuit of the running exerciser according to the present invention, Figure 2 is a circuit diagram showing a preferred embodiment of the constant speed control circuit of the running exerciser according to the present invention, Fig. 3 is a detailed circuit diagram of the error amplifier 160, the input unit 170, the oscillator 180, the comparative amplifier 190 of the constant speed control circuit of the running exercise machine according to the present invention (IC circuitry of Fig. 3 is named SS9470HD) Respectively.

One embodiment of the present invention is the same as the block diagram shown in FIG. The block diagram will be described as follows.

-Power supply unit 110: Receives the commercial power, the voltage is appropriately stepped down and rectified and supplied to the voltage required for each part. This part is not unique to the present invention.

-Rectifier 115: This part converts an AC voltage into a DC voltage to be used as a power source by supplying the DC power supply 100 to the DC motor. This part is common to all DC motors.

Filter unit 120: The rectified voltage is smoothly removed to supply the switching unit 130. This part is also common to all DC motors.

-Switching unit 130: Controls the actual motor, and controls the voltage applied time to the motor by connecting or disconnecting the DC power supply 100 supplied to the motor in accordance with the square wave signal of the comparative amplifier 190 Part consists of power devices such as FET or IGBT.

Current detection unit 140: detects the current flowing in the motor, this detection amount is sent to the amplifier 160 and the speed detection unit 150. Each of the following portions 150, 160, 170, 180, and 190, including the current detecting unit 140, is the core of the present invention as an element constituting the features of the present invention.

Error amplification unit 160: amplifies the current signal detected by the current detector 140 to convert the transfer to the voltage required for the comparison amplifier 190. In addition, if an overcurrent flows more than the current limit, a signal is also generated to suppress it and transmitted to the comparison amplifier 190.

-Input unit 170: The part that receives the voltage for controlling the motor rotation is equipped with a MAX adjuster for setting the maximum speed.

Oscillator 180: The oscillation unit 180 is a portion that oscillates the fundamental frequency for controlling the motor makes a triangular waveform and transmits to the comparison amplifier 190. The basic frequency is 18KHz.

Comparative amplifier 190: generating a square wave to drive the switching unit 130 by comparing the signal transmitted from the input unit 170 and the error amplifier 160 with the triangular wave transmitted from the oscillator 180. do. This signal is actually a signal for driving the motor.

-Overspeed detection unit 150: When the voltage applied to the motor is higher than the maximum voltage used, the rotational speed of the motor is faster than the set speed causes a safety problem, so in this case boil the relay of the power supply unit 110 to supply power (100) It is a circuit to block.

An embodiment in which the present invention having the above configuration is actually implemented as a circuit is shown in FIGS. 2 and 3. The operation will be described below with reference to the drawings.

The AC power supply 100 supplied through the power supply lines L1 and L2 of the power supply unit 110 of FIG. 2 is stepped down through the transistor T1 and rectified through the diodes D3, 4, 5, and 6, in the capacitor C8. It is smoothed and supplied to each part. In addition, electric power for driving the motor is rectified by the diode BD1 via the relay RY1 and then supplied to the filter unit 120 for pulsation removal.

The rectified input power supply 100 is for discharging the residual charges charged in the capacitor C3 of the filter unit 120 to prevent electric shock and the like during inspection and repair.

The voltage supplied from the variable resistor VR1 connected to the input terminals S1, S2, and S3 of the hybrid IC (SS9470470HD, 200) of FIG. 2 is divided to obtain a resistor R9 through the resistor R8 and the capacitor C3 of the input unit 170 of FIG. And integrated in the capacitor C4 connected to the hybrid terminal 200 terminal 13 of FIG. 2 and supplied to the operational amplifier U2B of the input unit 170 of FIG. This voltage becomes a reference signal for initially driving the motor, and then increases and decreases according to the signal of each part connected in response to the rotational speed of the motor.

In addition, the transistor Q3 and the resistors R19, R21 and the capacitor C9 of the oscillator 180 of FIG. 3 operate as a reference frequency oscillator together with the comparison amplifier 190 and a triangular waveform (basic) at the third terminal of the comparison amplifier 190. Frequency 18KHz). The comparison amplifier 190 compares the triangular wave signal with the signal transmitted from the input unit 170 and supplies it to the FETs Q1, Q2, Q6 of the switching unit 130 of FIG. It is to control the power supplied to. The switched power passes through the resistor R1 of the current detector 140 of FIG. 2, and according to Ohm's law, an electromotive force is generated across the resistor R1 and the voltage is divided by the resistors R10 and R14. The input of the comparison amplifier 190 is supplied to the operational amplifier U1B in the error amplifier 160 of 3 and compared with the maximum current limit set by the resistor R22 and the resistor R12 of the current detector 140 of FIG. It absorbs the voltage and limits the output. The important thing here is that the source potential is after the resistor R1 of the current detector 140 of FIG. 2 because of the source follower type switching, which is then a reference point of the compensation circuit operation. When the motor rotates in this manner, the current flow according to the load change is detected by the resistance R2 of the current detector 140 of FIG. 2. When the load increases, the rotation speed decreases and the current flowing to the motor increases. This is due to the impedance of the switching unit 130, the resistances R1 and R2 of the current detector 140 and the resistance components of the motor rotor. If the motor rotates normally, the effective current flows after the time delay of L / R, but a small current flows. However, if the rotation speed decreases, the rotation speed of the rotor decreases, so that the current flows through the resistance R2 of the current detector 140 of FIG. The current increases and the voltage across it also increases. This voltage is read and amplified by the U2A of the error amplifier 160 and divided by the resistors R18, VR2, and R17 connected to the terminals 4 and 5 of the hybrid part 200 of FIG. 2 and transferred to the input unit 170 of FIG. Done. This voltage is added to the existing input voltage in the input unit 170 to increase the speed of the rotor. On the contrary, if the rotor rotates faster than the set speed, due to the inductance of the rotor at the A + 1 and A-1 stages of the current detector 240 of FIG. If this voltage is increased, this voltage is smoothed by the resistor R8 connected to the third terminal of the hybrid unit 200 of FIG. 2 and the capacitor C5 of the input unit 170 of FIG. This slows down the rotor. This is possible because the end of the fuse F1 of the current detecting unit 140 of FIG. 2 and the end of the third terminal of the hybrid unit 200 are common terminals.

The speed detecting unit 150 detects the voltages at both ends of the rotor (A + 1 and A-1 of the current detecting unit 140 of FIG. 2) and the control circuit loses control (short circuit of the switching element and over input). The charge is accumulated in the resistors R20 and R22 of the overspeed detection unit 150, the transistor PC1 and the capacitor C10, and when the accumulated voltage is greater than the overspeed detection unit 150 and the zener diode ZD3 voltage, the power supply unit 110 relays. Boiling the connection of the relay RY1 of the speed detection unit 150 integrated with RY1 cuts off the power supply 100 to stop the motor and minimize the damage caused by this. This circuit is configured not to automatically recover until the main power source 100 is removed, which is consistent with several safety standards of the Savior countries.

By detecting the change on the running exercise belt in real time and correcting the changed value at high frequency, it eliminates the fatigue and risk factors of the exerciser's exercise and ensures comfortable exercise and improves the quality of various running exercise equipment. It can also contribute to the localization of running sports that are currently imported. In addition, this technology can be applied to the motor industry where load fluctuations are severe, enabling various devices with more precise control of rotation speed.

Claims (5)

In a running exerciser driven by a direct current motor, when the rotation speed of the direct current motor decreases, the current flowing through the rotor is detected and converted into a voltage, and then amplified and divided to add (IR compensation) to the input voltage of the motor. A current detector 140 which detects a current flowing in the rotor and sends the current to the error amplifier; An error amplifier unit 160 which amplifies the current signal detected by the current detector 140 and converts it into a voltage and transmits the voltage to the compensation terminal of the comparison amplifier 190; An oscillator 180 oscillating; an input unit 170 receiving a voltage for controlling the motor rotation; a signal transmitted from the input unit 170 and the error amplifier 160 and a signal transmitted from the oscillator 180 Comparative amplifier 190 for generating a square wave to drive the switching unit 130 by comparing the triangular wave; Switching to intermittently control the power supply 100 supplied to the motor in accordance with the square wave signal of the comparison amplifier 190 Constant speed control circuit of the running exercise machine, characterized in that comprising a unit (130). According to claim 1, When the speed of the DC motor is greater than the set speed, the current detection unit 140 in the input unit 170 to compensate for the reverse electromotive force of the both ends of the rotor of the DC motor to the input voltage of the DC motor Running filter characterized in that the filter formed of a resistor (R8) and a capacitor (C5) that can be received after smoothing by detecting the counter electromotive force of both ends (A + 1, A-1) of the rotor) Constant speed control circuit. According to claim 1, It is electrically connected to both ends (A + 1, A-1) of the motor rotor of the current detector 140, the voltage of the both ends (A + 1, A-1) of the maximum When the voltage is higher than the constant speed control circuit of the running exercise machine, characterized in that it comprises a speed detection unit 150 for boiling the power supply 100 by automatically blocking the relay of the power supply unit 110 of the motor. The current detecting unit 140 includes a resistor R1 for detecting a current switched by the switching unit 130, and the current detected by the resistor R1 includes the error amplifying unit 160. And the input voltage from the error amplifier 160 to the comparison amplifier 190 when an overcurrent flows through the current detection resistor R1 to the current detector 140 and the error amplifier 160. And a resistor (R12, R22) for limiting the maximum current flowing through the current detection resistor (R1) so as to be absorbed. In a running motor driven by a DC motor, when the rotation speed of the DC motor decreases, the current flowing through the rotor is detected, converted into a voltage, amplified, and added to the input voltage of the motor, and the rotation speed of the DC motor increases. The constant speed control method of the running exercise machine to maintain the constant speed running by detecting the counter electromotive force of both ends of the rotor during the subtraction.