Leg.h

00001 /**
00002 @file Leg.h
00003 
00004 @brief Header file containing member functions and variables
00005 
00006 */
00007 
00008 #ifndef LEG_H
00009 #define LEG_H
00010 
00011 #include "mbed.h"
00012 #include "Utils.h"
00013 
00014 /**
00015 @brief mbed library for controlling a 3DOF robotic leg such as though found on the Lynxmotion MAH3-R Hexapod.
00016 @brief The library solves the inverse kinematic equations of the leg to position the foot at a
00017 @brief specified [X,Y,Z] cordinate.
00018 
00019 @see http://www.lynxmotion.com/c-157-mah3-r.aspx
00020 
00021 @brief Revision 0.1
00022 
00023 @author Craig A. Evans
00024 @date   May 2015
00025  *
00026  * Example:
00027  * @code
00028 
00029 #include "mbed.h"
00030 #include "Leg.h"
00031 
00032 Serial serial(USBTX,USBRX);
00033 Leg leg(p21,p22,p23);
00034 
00035 int main()
00036 {
00037     serial.baud(115200);
00038 
00039     leg.set_link_lengths(28.0,58.0,125.0);  // set leg dimensions
00040 
00041     Timer t;  // timer for calculation (~80 us on LPC1768)
00042     t.start();
00043     vector_t angles = leg.solve_inverse_kinematics(80.0,0.0,-100.0);  // solve IK equations
00044     t.stop();
00045 
00046     serial.printf("\nSolution time = %f us\n",1e6*t.read());
00047 
00048     leg.move(angles);  // update servo angles
00049 
00050     while(1) {
00051 
00052     }
00053 }
00054 
00055  * @endcode
00056  */
00057 
00058 class Leg
00059 {
00060 
00061 public:
00062     /** Create a Leg object connected to the specified pins. MUST be PWM-enabled pins.
00063     *
00064     * @param coxa_pin Signal line for the coxa servo
00065     * @param femur_pin Signal line for the femur servo
00066     * @param tibia_pin Signal line for the tibia servo
00067     *
00068     */
00069     Leg(PinName coxa_pin, PinName femur_pin, PinName tibia_pin);
00070 
00071     /**  Solve inverse kinematic equations to get the required joint angles
00072     * The x-axis is defined as the common normal of the joints.
00073     * The coxa joint rotates about the z-axis.
00074     * The y-axis is defined by the right-hand rule.
00075     * @param x Distance away from body
00076     * @param y Distance in front/behind the hip
00077     * @param z Height of foot
00078     * @returns a vector containing the joint angles [coxa,femur,tibia]
00079     */
00080     vector_t solve_inverse_kinematics(float x, float y, float z);
00081 
00082     /**  Set link lengths (in mm).
00083     * @param coxa_length Length of coxa
00084     * @param femur_length Length of femur
00085     * @param tibia_length Length of tibia
00086     */
00087     void set_link_lengths(float coxa_length, float femur_length, float tibia_length);
00088 
00089     /**  Move servos to calculated angles
00090     * @param a vector containing the joint angles [coxa,femur,tibia]
00091     */
00092     void move(vector_t angles);
00093 
00094 private:
00095 
00096 public:
00097 
00098 
00099 
00100 private:  // private variables
00101     // pins for servos
00102     PwmOut* coxa_servo;
00103     PwmOut* femur_servo;
00104     PwmOut* tibia_servo;
00105     //Serial* serial;  // for comms
00106 
00107     // link lengths
00108     float coxa_length_;
00109     float femur_length_;
00110     float tibia_length_;
00111 
00112 };
00113 
00114 #endif