Class OmniWheels4X

Inheritance Relationships

Base Type

Class Documentation

class OmniWheels4X : public OpenSoT::Constraint<Eigen::MatrixXd, Eigen::VectorXd>

The OmniWheels4X class implements a constraint to map base velocities into (omni-)wheels for a 4 drive case.

The kinematic model is based on: “An admittance-controlled wheeled mobile manipulator for mobility assistance:

Human–robot interaction estimation and redundancy resolution for enhanced force exertion ability” by Hongjun Xing et al., Mechatronics, April 2021

Public Types

typedef std::shared_ptr<OmniWheels4X> Ptr

Public Functions

OmniWheels4X(const double l1, const double l2, const double r, const std::vector<std::string> joint_wheels_name, const std::string base_link, XBot::ModelInterface &robot)

OmniWheel4X maps base velocities (XY-YAW) into wheels velocities. 

                            | x
                            |
                       y____|

                l1
              ------
       __          __
      |fl|________|fr|
      |__|        |__| |
         |        |    | l2
         |        |    |
         |        |
       __|        |__
      |hl|________|hr|
      |__|        |__|

Note

we suppose the base_link at the center of the mobile base

Note

we assume a floating base robot

Parameters

  • l1 – y distance from the base frame to the center of the wheel (see figure)

  • l2 – x distance from the base frame to the center of the wheel (see figure)

  • r – wheel radius

  • joint_wheels_name – ordered list of joint names representing the wheels [fl, fr, hl, hr]

  • base_link – of the mobile base assumed to be at the center

  • x – initial configuration of the robot when creating the constraint

  • robot – the robot model

virtual void update()

update the constraint

Parameters

x – state vector

inline void setIsGlobalVelocity(bool is_global_velocity)

setIsGlobalVelocity set the flag to consider the velocity in the global frame

Parameters

is_global_velocity – default is false

inline bool getIsGlobalVelocity() const

getIsGlobalVelocity get the flag to consider the velocity in the global frame

Returns

true or false