Balancing robot final year project

//------------------------------------------------------------------// You can find the Atmel studio folder of the robot's code and schemantic here: https://www.dropbox.com/sh/fjjwcn1w03... //-----------------------------------------------------------------// //-----------------------------------------------------------------// Usefull informations: PID controller: http://www.cds.caltech.edu/~murray/co... Complementary filter: http://d1.amobbs.com/bbs_upload782111... //-----------------------------------------------------------------// Components: Microcontroller: ATmega32 Gyroscope: mpu-6050 (in the video I used a LISY300) Accelerometer mpu-6050 (in the video I used a BMA180) Encoder: Ball mouse Motor Controller: Pololu TB6612FNG Motors: Old DC motors madi in Japan :) SM - E048 12500 RPM without load. Current: 0.1 A Without load 1.5 A When the wheels are changing the direction of rotation, or when going uphill. Battery: Electric drill 9.6V NiMH Wheels: Toy tractor Geer ratio: 1:8 Bluetooth-SerialPort converter: hc - 05 Complementary filter (For the angular velocity I used only the Gyro) With the use of euler angles balancing end turning in inclined surface is more easier Remote Controller: ATmega328P PS2 Analoge Stick Bluetooth-SerialPort converter: hc - 05 //-----------------------------------------------------------------// The requested velocity when the robot is standing still is: ReqVelocity = RobotPosition(mm) * positionKP poitionKP = 0.008 The requested angle is calculated by a PI controller. The setpoint for this controller is ReqVelocity. The measured velocity is filtered by a Low pass filter. the output of the controller is the ReqAngle velocityKP = 2 velocityKI = 1.64 PIDoutput is constrained between = -20,20 this is the maximum angle that the robot would try to reach when accelerating. The maximum value whereby the ‘I’ can change is 6.6. So when calculating the integrator value then error can constrained between +-maxIchange/velocityKI The requested PWM for the motors is calculated by a PD controller. The setpoint for this controller is ReqAngle. To eliminate the derivative spikes D is calculated from the measured angle change, not from the error. angleKP = 40 angleKD = -4.5 (this is minus because it isn’t calculated from the error) PIDoutput is constrained between -255, 255 The output of this controller is also filtered with a Low pass filter To keep the robot’s orientation another PWM value is calculated and then added to one of the motors and subtracted from the other. orientationKP = 5 orientationKD = 0.1 the whole program runs in a loop 100 times in a second. If the value of the filters would changed, than the PID’s value would also need to be changed. The low pass filter’s code with fixed timing is: filteredARRAY[0] = rawDATA*LPFgain + filteredARRAY[1]*(1-LPFgain); filteredARRAY[1] = filteredARRAY[0]; velocity LPFgain = 0.35 //0.45 PWM LPFgain = 0.2 //0.45 reqeustedVelocity LPFgain = 0.05 (this is to smooth the setpoint changes)