Diff: pid_controller.hpp

Revision:

0:fca62f1974fa

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pid_controller.hpp	Mon Aug 23 17:02:09 2021 +0000
@@ -0,0 +1,68 @@
+#ifndef PID_CONTROLLER_HPP
+#define PID_CONTROLLER_HPP
+
+#include <vector>
+
+class PIDControl
+{
+    public:
+    struct Bound
+    {
+        double upper;
+        double lower;
+    };
+    struct Parameter
+    {
+        double kp;
+        double ki;
+        double kd;
+        Bound bound;
+        Bound threshold;
+    };
+  
+    PIDControl(const Parameter& param) : param_(param)
+    {
+        err_.resize(3,0);
+        control_input_.resize(2,0);
+    };
+    ~PIDControl() = default;
+
+    const double& calculate(const double& ref, const double& cur);
+
+    const Parameter& parameter(void) const { return param_; };
+    void parameter(const Parameter& param) { param_ = param; };
+    
+    double calculate(double ref, double cur, double time_step)
+    {        
+        err_[2] = ( (ref - cur)-err_[0] ) / time_step;
+        err_[0] = ref - cur;
+        
+        // calculate control input
+        control_input_[0] = param_.kp*err_[0] + param_.ki*err_[1] + param_.kd*err_[2];
+        
+        // limit of control input
+        control_input_[0] = min(control_input_[0], param_.bound.upper);
+        control_input_[0] = max(control_input_[0], param_.bound.lower);
+        
+        // update
+        control_input_[1] = control_input_[0];
+        err_[1] += err_[0] * time_step;
+        
+        // limit of i gain
+        err_[1] = min(err_[1], param_.bound.upper);
+        err_[1] = max(err_[1], param_.bound.lower);
+        
+        if( (ref - cur < param_.threshold.upper) && (ref - cur > param_.threshold.lower) )
+            return 0;
+        
+        return control_input_[0];
+    }
+  
+    private:
+    Parameter param_;
+
+    std::vector<double> err_;   //[current_error, error_integral, error_diff]
+    std::vector<double> control_input_;
+};
+
+#endif
\ No newline at end of file