joint_limit.cpp

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#include <exotica_core_task_maps/joint_limit.h>
 
REGISTER_TASKMAP_TYPE("JointLimit", exotica::JointLimit);
 
namespace exotica
{
void JointLimit::AssignScene(ScenePtr scene)
{
    scene_ = scene;
    Initialize();
}
 
void JointLimit::Initialize()
{
    safe_percentage_ = parameters_.SafePercentage;
 
    if (scene_->get_num_velocities() > 0)
    {
        // Position and velocity joint limits
        N = scene_->get_num_state_derivative();
    }
    else
    {
        // Kinematic joint limits
        N = scene_->GetKinematicTree().GetNumControlledJoints();
    }
}
 
int JointLimit::TaskSpaceDim()
{
    return N;
}
 
void JointLimit::Update(Eigen::VectorXdRefConst q, Eigen::VectorXdRef phi)
{
    if (phi.rows() != N) ThrowNamed("Wrong size of phi!");
 
    const Eigen::MatrixXd& limits = scene_->GetKinematicTree().GetJointLimits();
    const Eigen::VectorXd& low_limits = limits.col(0);
    const Eigen::VectorXd& high_limits = limits.col(1);
    const Eigen::VectorXd tau = 0.5 * safe_percentage_ * (high_limits - low_limits);
 
    // apply lower bounds
    phi = (q.array() < (low_limits + tau).array()).select(q - low_limits - tau, phi);
    // apply higher bounds
    phi = (q.array() > (high_limits - tau).array()).select(q - high_limits + tau, phi);
}
 
void JointLimit::Update(Eigen::VectorXdRefConst q, Eigen::VectorXdRef phi, Eigen::MatrixXdRef jacobian)
{
    if (jacobian.rows() != N || jacobian.cols() != N) ThrowNamed("Wrong size of jacobian! " << N);
    Update(q, phi);
 
    // The jacobian is piece-wise: It's 0 when within limits, and 1 when outside.
    const Eigen::MatrixXd& limits = scene_->GetKinematicTree().GetJointLimits();
    const Eigen::VectorXd& low_limits = limits.col(0);
    const Eigen::VectorXd& high_limits = limits.col(1);
    const Eigen::VectorXd tau = 0.5 * safe_percentage_ * (high_limits - low_limits);
    for (int i = 0; i < N; i++)
    {
        if (q(i) >= low_limits(i) + tau(i) && q(i) <= high_limits(i) - tau(i))
        {
            jacobian(i, i) = 0;
        }
        else
        {
            jacobian(i, i) = 1;
        }
    }
}
 
void JointLimit::Update(Eigen::VectorXdRefConst x, Eigen::VectorXdRef phi, Eigen::MatrixXdRef jacobian, HessianRef hessian)
{
    if (hessian.size() != N) ThrowNamed("Wrong size of hessian! " << N);
    // Hessian is 0.
    Update(x, phi, jacobian);
}
 
void JointLimit::Update(Eigen::VectorXdRefConst x, Eigen::VectorXdRefConst u, Eigen::VectorXdRef phi)
{
    if (phi.rows() != N) ThrowNamed("Wrong size of phi!");
 
    // Build limits vector for state limits:
    Eigen::VectorXd low_limits(N), high_limits(N);
 
    const Eigen::MatrixXd& limits = scene_->GetKinematicTree().GetJointLimits();
    low_limits.head(scene_->get_num_positions()) = limits.col(0);
    high_limits.head(scene_->get_num_positions()) = limits.col(1);
 
    low_limits.tail(scene_->get_num_velocities()) = -scene_->GetKinematicTree().GetVelocityLimits();
    high_limits.tail(scene_->get_num_velocities()) = scene_->GetKinematicTree().GetVelocityLimits();
 
    const Eigen::VectorXd tau = 0.5 * safe_percentage_ * (high_limits - low_limits);
 
    // apply lower bounds
    phi = (x.array() < (low_limits + tau).array()).select(x - low_limits - tau, phi);
    // apply higher bounds
    phi = (x.array() > (high_limits - tau).array()).select(x - high_limits + tau, phi);
}
 
void JointLimit::Update(Eigen::VectorXdRefConst x, Eigen::VectorXdRefConst u, Eigen::VectorXdRef phi, Eigen::MatrixXdRef dphi_dx, Eigen::MatrixXdRef dphi_du)
{
    if (dphi_dx.rows() != N || dphi_dx.cols() != N) ThrowNamed("Wrong size of dphi_dx! " << N);
    if (phi.rows() != N) ThrowNamed("Wrong size of phi!");
 
    // Build limits vector for state limits:
    Eigen::VectorXd low_limits(N), high_limits(N);
 
    const Eigen::MatrixXd& limits = scene_->GetKinematicTree().GetJointLimits();
    low_limits.head(scene_->get_num_positions()) = limits.col(0);
    high_limits.head(scene_->get_num_positions()) = limits.col(1);
 
    low_limits.tail(scene_->get_num_velocities()) = -scene_->GetKinematicTree().GetVelocityLimits();
    high_limits.tail(scene_->get_num_velocities()) = scene_->GetKinematicTree().GetVelocityLimits();
 
    const Eigen::VectorXd tau = 0.5 * safe_percentage_ * (high_limits - low_limits);
 
    // apply lower bounds
    phi = (x.array() < (low_limits + tau).array()).select(x - low_limits - tau, phi);
    // apply higher bounds
    phi = (x.array() > (high_limits - tau).array()).select(x - high_limits + tau, phi);
 
    for (int i = 0; i < N; i++)
    {
        if (x(i) >= low_limits(i) + tau(i) && x(i) <= high_limits(i) - tau(i))
        {
            dphi_dx(i, i) = 0;
        }
        else
        {
            dphi_dx(i, i) = 1;
        }
    }
}
 
void JointLimit::Update(Eigen::VectorXdRefConst x, Eigen::VectorXdRefConst u, Eigen::VectorXdRef phi, Eigen::MatrixXdRef dphi_dx, Eigen::MatrixXdRef dphi_du, HessianRef ddphi_ddx, HessianRef ddphi_ddu, HessianRef ddphi_dxdu)
{
    // Hessian is 0.
    Update(x, u, phi, dphi_dx, dphi_du);
}
 
}  // namespace exotica