Interpretation of two machine vision system circuit design solutions - circuit diagram reading every day (77)

The robot walking circuit is composed of two units of a driving circuit and a forward and reverse circuit of the DC motor. The circuit constitutes the robot walking circuit by using the multi-resonant circuit composed of 555, the synchronous counter 74LS196, the seven-segment decoder 74LS248, the double JK flip-flop and other basic unit circuits through the cascade combination of the above basic circuits. The circuit effectively realizes the walking and retreating of the robot, and controls the walking time by adjusting the magnitude of the resistance, and the time is displayed on the digital display tube. The conduction direction of the robot is controlled by the conduction and cut-off of the triode to meet the requirements of the design circuit.

Circuit principle system block diagram

Scheme one circuit diagram

555 constitutes a multi-resonant circuit to generate a square wave signal, 74LS196 constitutes a decimal counter, 74LS248 controls a seven-segment common cathode digital tube display circuit display, the counter count full trigger signal triggers a double JK flip-flop, and the double JK flip-flop is under the action of a trigger signal The output has a high-low level transition, and the trigger signal generates a positive and negative transition of the differential pressure across the DC motor. The DC motor is reversed to achieve forward and backward movement of the robot. Each switch in the circuit controls the direction of rotation and rotation of the motor and the time.

Scheme 2 circuit diagram

The 74LS123 timer generates a rectangular wave signal, which is composed of 74HC161 and NAND gate 74HC03 to form a decimal counter. 74LS248 controls the seven-segment common cathode digital tube display circuit display. The counter counts full to generate a trigger signal to trigger a dual JK flip-flop, double JK flip-flop. The output generates a high-low level transition under the action of the trigger signal, and the DC motor drive circuit changes the voltage direction across the motor to change the motor steering. The switch in the circuit can also be motor brake, positive and negative.

Robot walking circuit working principle

The multi-resonant circuit composed of 555 generates a square wave signal to the 74LS196 clock terminal to trigger the 74LS196 up counter count, and drives the seven-segment common cathode digital tube to display the count through the 74LS248. The up counter counts up to ten, and the falling edge signal is driven by the 74HC20 NAND gate to drive the double JK flip-flop to make the T' flip-flop output of the JK flip-flop non-exact, thereby driving the switching circuit formed by the triode, and turning on and off the respective triodes. To realize the positive and negative jump of the differential pressure across the DC motor, drive the forward and reverse rotation of the DC motor to realize the forward and reverse of the trolley. Among them, by adjusting four single-pole five-throw switches, the square wave period of the multi-harmonic circuit can be changed to adjust the advance and retreat time of the trolley.

The multi-resonant circuit generates a square wave signal to the 74196 clock terminal, and drives 74196 to count up. In the figure, 74196 is connected to the decimal add-up counter. When the count is full, the 74HC20 NAND gate is connected to the clear terminal for clearing. As the count reaches 10, it will be cleared immediately and will not be displayed on the digital tube. Therefore, the signal is very weak at this time. It can not be used as a trigger signal to drive the JK trigger. The JK trigger trigger signal is counted to 9 when passing the 74HC20. The output falling edge signal is triggered. The digital display circuit is displayed by a seven-segment common cathode digital tube driven by a 74LS248.

Electronic enthusiast network technology editors comment analysis:

The robot walking circuit basically conforms to the basic requirements of automatic advance and retreat after a fixed period, automatic timing, use of a dry battery of 5V voltage, and adjustable time for the robot to walk. (1) The motor stops rotating in the way of energy consumption braking: the energy consumption braking can be realized by connecting a resistor in parallel with the motor; (2) Adjusting the motor speed: the sliding rheostat can be connected in series with the motor, and the motor speed can be changed by changing the resistance. However, it can only be qualitatively adjusted. Because the motor speed is related to multiple physical quantities, this method should be cautious; (3) The line layout can be optimized to facilitate expansion.