bczsalba / dovediff

A simple 3 joint inverse kinematics solver for the Arduino.

dovediff

A relatively simple triple joint inverse kinematics solver for the Arduino.

Usage

dovediff contains an example of use. In essence, you need to find your servos' approximate range of motion, and let the program know using a ServoInfo type. After each servo for an arm is configured, you can create an Arm that combines them all. Make sure you know which pin is hooked up to which arm!

#include "Arm.h"
using namespace Arms;

arm = {
    // Servo on pin 3 (base):
    //   - Turns 180 degrees when instructed for 175.0 (ratio: 175.0 / 180.0)
    //   - Has a 0 degree offset
    //   - Should be limited to only turn 90*ratio degrees
    //   - Is attached to an arm with 0 length
    ServoInfo{ makeServo(3), 175.0 / 180.0, 0, 90 }, 0,

    ServoInfo{ makeServo(5), 170.0 / 180.0, 0, 50 }, 11.7,
    ServoInfo{ makeServo(6), 250.0 / 180.0, 0, 180 }, 20.0,
};

void loop() {
    Position pos = {rand(0, 30), 0, rand(0, 30)};

    if (moveArm(arm, &pos)) {
        delay(600);        

    } else {
        Serial.print("Could not move to ");
        Serial.print(pos.x);
        Serial.print(";");
        Serial.print(pos.y);
        Serial.print(";");
        Serial.println(pos.z);
    }
}

The project also includes a simple utility to get a position from 2 proximity sensors, Fields:

#include "Fields.h"
using namespace Fields;

Fields::DepthSensor xSensor = makeSensor(4, 11);
Fields::DepthSensor ySensor = makeSensor(8, 9);

void setup() {
    xSensor = makeSensor(4, 11);
    ySensor = makeSensor(8, 9);
}

void loop() {
    Serial.print("x: ");
    Serial.println(readSensor(xSensor));

    Serial.print("y: ");
    Serial.println(readSensor(ySensor));
}

Limitations

This project was made on and for low-accuracy equipment in a very limited timespan. The math is only accurate enough for the purposes we needed it for, and your mileage may vary. The biggest issue we had was that the Y axis was seemingly flipped. Since we could temporary fix this problem well enough for what we needed, we didn't (yet) figure out the problem.