Struct TwoLinkArm 

pub struct TwoLinkArm { /* private fields */ }

A planar two-link arm: the textbook arm with a closed-form inverse.

Two links of fixed length in a plane, with a shoulder and an elbow joint. tip is forward kinematics; joints_for is the analytic inverse, returning the shoulder and elbow angles that place the hand at a target, for the chosen Elbow branch.

Examples

use pamoja_kit::{Elbow, TwoLinkArm};

let arm = TwoLinkArm::new(1.0, 1.0);
// Place the hand, then recover the joint angles for it.
let (x, y) = arm.tip(0.5, 0.7);
let (q1, q2) = arm.joints_for(x, y, Elbow::Up).unwrap();
assert!((q1 - 0.5).abs() < 1e-4 && (q2 - 0.7).abs() < 1e-4);

// A target beyond the arm's reach has no solution.
assert!(arm.joints_for(5.0, 0.0, Elbow::Up).is_none());

Implementations

impl TwoLinkArm

pub fn new(l1: f32, l2: f32) -> Self

Creates an arm from its two link lengths.

Arguments

• l1 - the first (shoulder) link length; its magnitude is used.
• l2 - the second (elbow) link length; its magnitude is used.

Returns

The arm.

pub fn reach(&self) -> (f32, f32)

Returns the closest and farthest distances the hand can reach from the shoulder.

Returns

(min, max), where min is |l1 - l2| and max is l1 + l2.

pub fn tip(&self, shoulder: f32, elbow: f32) -> (f32, f32)

Returns the hand position for given joint angles (forward kinematics).

Arguments

• shoulder - the first joint angle, in radians from the x axis.
• elbow - the second joint angle, in radians relative to the first link.

Returns

The hand (x, y).

pub fn joints_for(&self, x: f32, y: f32, elbow: Elbow) -> Option<(f32, f32)>

Returns the joint angles that place the hand at a target (inverse kinematics).

Arguments

• x - the target x coordinate.
• y - the target y coordinate.
• elbow - which Elbow branch to solve for.

Returns

Some((shoulder, elbow)) for a reachable target, or None if the target lies outside the arm’s reach.

Trait Implementations

impl Clone for TwoLinkArm

fn clone(&self) -> TwoLinkArm

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for TwoLinkArm

impl Debug for TwoLinkArm

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.