Lib.rs

A library to compute S-Curve trajectories. It can be used to generate motion profiles for robotics.

What is an S-Curve?

An S-Curve is a trajectory which is constrained to maximum jerk, acceleration and velocity. An S-Curve consists of 7 phases:

• constant maximum jerk until the desired acceleration is reached
• constant maximum acceleration phase
• constant minimum jerk until the desired velocity is reached with an acceleration of zero
• constant velocity phase
• constant minimum jerk until the minimum acceleration is reached
• constant minimum acceleration phase
• constant maximum jerk until the acceleration is zero and the desired position and end velocity is reached

In the picture below you can see an S-Curve Profile which goes from Position 0 to position 10 within 5.5 seconds with a start and end velocity of 0 , a maximum jerk of 3, a maximum acceleration of 2 and a maximum velocity of 3.

Example

use s_curve::*;
let constraints = SCurveConstraints {
            max_jerk: 3.,
            max_acceleration: 2.0,
            max_velocity: 3.};
let  start_conditions = SCurveStartConditions {
    q0: 0., // start position
    q1: 10., // end position
    v0: 0., // start velocity
    v1: 0. // end velocity
};
let input  =  SCurveInput{constraints, start_conditions};
let (params,s_curve) = s_curve_generator( & input,Derivative::Velocity);
for i in 0..101 {
    println!("{}", s_curve(i as f64 * params.time_intervals.total_duration() / 100.));
}

License

Copyright (c) 2020 Marco Boneberger Licensed under either of Apache License, Version 2.0 or MIT license at your option.