human-modelling-framework/src/MotorPrimitives.ts

Human sensorimotor control modelling framework based on Markkula et al's paper (DOI: 10.1007/s00422-017-0743-9)

import { Solver, Outcome, Derivative } from "odex";

interface Point {
  x: number;
  y: number;
}

export class MotorPrimitives {
  // parameters
  T: number;
  a_v: number;
  a_x: number;
  a_y: number;
  a_r: number;
  a_z: number;
  a_p: number;
  b: number;
  c_0: number;

  // simulation parameters
  t0: number; //initial time value
  duration: number; //range of ODE solving
  dt: number;

  // current ODE values
  y: number[] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
  solver: Solver;
  outVal = new Array<Point>();

  constructor(t: number, y?: number[]) {
    if (y != undefined) {
      this.y = y;
      this.outVal.push({ x: this.t0, y: y[0] - y[1] });
    } else {
      this.outVal.push({ x: 0, y: 0 });
    }
    this.setTarget(t);
    this.a_v = 50;
    this.a_x = 1;
    this.a_y = 1;
    this.a_r = 50;
    this.a_z = 0.01;
    this.a_p = 0.285;
    this.b = 10;
    this.c_0 = 10;
    this.solver = new Solver(this.y.length);
    this.solver.denseOutput = true;
    this.t0 = 0;
    this.dt = 0.01;
    this.duration = this.dt;
  }

  // Implementation of Schaal algorithm
  schaal: (
    T: number,
    a_v: number,
    a_x: number,
    a_y: number,
    a_r: number,
    a_z: number,
    a_p: number,
    b: number,
    c_0: number
  ) => Derivative = (T, a_v, a_x, a_y, a_r, a_z, a_p, b, c_0) => (x, y) => {
    // Equations adapted from Degallier's thesis
    let dy = new Array<number>();
    let DeltaW = [Math.max(0, T - y[0]), Math.max(0, -T - y[1])];

    dy[2] = a_v * (-y[2] + DeltaW[0]);
    dy[3] = a_v * (-y[3] + DeltaW[1]);
    dy[4] = -a_x * y[4] + (y[2] - y[4]) * c_0;
    dy[5] = -a_x * y[5] + (y[3] - y[5]) * c_0;
    dy[6] = -a_y * y[6] + (y[4] - y[6]) * c_0;
    dy[7] = -a_y * y[7] + (y[5] - y[7]) * c_0;
    dy[8] = a_r * (-y[8] + (1 - y[8]) * b * y[2]);
    dy[9] = a_r * (-y[9] + (1 - y[9]) * b * y[3]);
    dy[10] = -a_z * y[10] + (y[6] - y[10]) * (1 - y[8]) * c_0;
    dy[11] = -a_z * y[11] + (y[7] - y[11]) * (1 - y[9]) * c_0;
    dy[0] = a_p * (Math.max(0, dy[10]) - Math.max(0, dy[11])) * c_0;
    dy[1] = a_p * (Math.max(0, dy[11]) - Math.max(0, dy[10])) * c_0;

    return dy;
  };
  setTarget(t: number) {
    this.T = t / 2;
  }
  solve() {
    let solveOut = this.solver.solve(
      this.schaal(
        this.T,
        this.a_v,
        this.a_x,
        this.a_y,
        this.a_r,
        this.a_z,
        this.a_p,
        this.b,
        this.c_0
      ),
      this.t0,
      this.y,
      this.t0 + this.duration,
      this.solver.grid(this.dt, (x, y) => {
        if (x != this.t0) this.outVal.push({ x: x, y: y[0] - y[1] });
      })
    );
    this.y = solveOut.y;
    this.t0 = solveOut.xEnd;
  }

  get2DValues() {
    return this.outVal;
  }

  getValues() {
    let y = [];
    this.outVal.forEach(element => {
      y.push(element.y);
    });
    return y;
  }
}