Tipo Test Exam

Considering the motor actuating on a given joint,. All options are correct. the inertia that the considered motor experiences depends on the configuration of the outward joints. causes a reaction force/torque on the inward link. gravity acting on the outward links exerts a weight force on the considered motor.

One of the following statements about the independent nested control is incorrect. Controllers must be tuned to optimize the closed-loop performance at an average operating point. The addition of the gravity feedforward term improves the controller performance. Inertia variation and other dynamic coupling forces are not explicitly dealt with. High accuracy may be achieved even if the gear ratio is low.

One of the following statements about the model-based control is incorrect. The multivariable control problem is not divided into several single-input single-output control problems. Only linear dynamics are considered. It is applied when the gearing ratio is low or non-existent. It is based on the robot dynamic model.

Comparing independent control and computed torque model-based control,. coupling effects are more pronounced in the computed torque model-based control. independent controllers usually lead to better performance than computed torque controllers at all velocities. computed torque model-based controllers present best performance and zero steady-state error at all velocities if integral action is used. independent PD controllers ensure zero steady-state error even in presence of external disturbances.

One of the following statements about joint trajectory sampling is correct: It is not a necessary step for the kinematic control. It is necessary to provide discrete-time references to the dynamic control. It is the first step of the kinematic control. Only positions are provided as set-points for the dynamic control.

One of the following tasks is not necessary for kinematic control when the desired end-effector trajectory is point-to-point: Convert a motion specification into an analytical Cartesian trajectory. Using inverse kinematics, convert some Cartesian poses into joint coordinates. Sample the joint trajectories to generate references for the dynamic controller. Interpolate the joint coordinates of the key points, generating a continuous trajectory which goes through or approaches the required joint coordinates.

Concerning the feedforward model-based control, ... only the position reference information is used to build the feedforward term. the feedback term provides the joint forces/torques required for the reference position, velocity, and acceleration. the gain matrices to be tuned are non-diagonal. the feedback term compensates for uncertainties and external disturbances.

One of the following statements about conversion from Cartesian poses into joint coordinates is incorrect: Singularities and multiple solutions are considered. Forward kinematics are applied. It is a necessary step for kinematic control. Inverse kinematiss are applied.

Concerning the Lagrangian energy-based method, ... the final equations depend on the position of the link centres of mass. it requires computing some variables by working outwards and then computing others by working inwards. it provides an estimation of the friction term. all intermediate variables have a physical meaning.

When reduction gearboxes are used, ... the joint velocity at the mechanical axis is lower than the joint velocity at the actuator axis. the joint acceleration at the mechanical axis is higher than the joint acceleration at the actuator axis. the torque at the mechanical axis is lower than the torque at the actuator axis. All options are incorrect.

When reduction gearboxes are used, ... All options are correct. the torque at the mechanical axis is lower than the torque at the actuator axis. the joint acceleration at the mechanical axis is lower than the joint acceleration at the actuator axis. the joint velocity at the mechanical axis is higher than the joint acceleration at the actuator axis.

One of the following tasks is not necessary for kinematic control when the desired end-effector trajectory is point-to-point: Interpolate the joint coordinates of the key points, generating a continuous trajectory which goes through or approaches the required joint coordinates. Sample the joint trajectories to generate references for the dynamic controller. Using inverse kinematics, convert some Cartesian poses into joint coordinates. Sample the desired Cartesian trajectory to obtain a finite number of poses.

One of the following statements about point-to-point trajectories is not correct: The robot is intended to describe a specific and a priori known Cartesian trajectory. The path does not matter, but only the final destination point does. They are easier to compute than continuous trajectories. The robot axes may be moved either at once or in shifts.

The friction term of the robot dynamic model. might become the least dominant force/torque for robots with reduction gearboxes. is reduced when the gear ratio increases. may include stiction and viscous friction. is linear with joint velocity.

When reduction gearboxes are used,. All options are incorrect. the joint velocity at the mechanical axis is higher than the joint velocity at the actuator axis. the joint acceleration at the mechanical axis is higher than the joint acceleration at the actuator axis. the torque at the mechanical axis is higher than the torque at the actuator axis.

Concerning the gravity term of the robot dynamic model,. all its elements are always negative. it might be neglected for few degree-of-freedom robots. it does not depend on the robot configuration. it is the dominating term when the robot is stationary or moving slowly.

Concerning Cartesian trajectory generation,. it is always a necessary step for kinematic control. it is the last step of the kinematic control. the information provided by the user must include spatial localizations, type of trajectory, and time issues. it only includes position interpolation.

The Newton-Euler's recursive method. has a higher computational cost than the Lagrangian energy-based algorithm. is based on inverse kinematics. requires computing some variables by working outwards, and then compute others by working inwards. provides structured dynamic equations.

When reduction gearboxes are used,. All options are incorrect. the joint velocity at the mechanical axis is higher than the joint velocity at the actuator axis. the torque at the mechanical axis is lower than the torque at the actuator axis. the joint acceleration at the mechanical axis is higher than the joint acceleration at the actuator axis.

Robot inverse dynamics. allow determining the forces and torques necessary to achieve some given joint coordinates, velocities, and accelerations. allow determining the position and orientation of the end effector with respect to a fixed coordinate frame. determine the joint coordinates necessary to achieve a given position and orientation of the end effector. determine the joint coordinates, velocities, and accelerations caused by some given joint forces and torques.

Concerning the gravity term of the robot dynamic model,. it is the dominating term when the robot is stationary or moving slowly. it might be neglected for few degree-of-freedom robots. all its elements are always negative. it does not depend on the robot configuration.

One of the following criteria is not considered by kinematic control: Invested time to perform the task. Accuracy of the joint coordinate trajectories. Physical constraints of the actuators. Accuracy of the end-effector trajectory in the Cartesian space.

The Coriolis matrix of the robot dynamic model. might be neglected for few degree-of-freedom robots. factors the centripetal and coupling velocity terms. does not depend on the robot configuration. is symmetric.

One of the following position representations cannot be interpolated: Homogeneous Transformation Matrices. Quaternions. Euler angles. All the representations can be interpolated.

Comparing independent control and computed torque model-based control, ... computed torque model-based controllers need more computational power than independent controllers. high performance microprocessors are usually needed to implement independent controllers. coupling effects are more pronounced in the computed torque model-based control. independent controllers usually lead to better performance than computed torque controllers at all velocities.

Concerning the Newton-Euler's recursive method ... the final equations do not depend on the position of the link centres of mass. all intermediate variables have a physical meaning. it makes use of all information contained in the homogeneous transformation matrices defined in the forward kinematics. it provides an estimation of the friction term.

Concerning the feedforward model-based control,. only the position reference information is used to build the feedforward term. the feedback term provides the joint forces/torques required for the reference position, velocity, and acceleration. the feedback term compensates for uncertainties and external disturbances. the gain matrices to be tuned are non-diagonal.

One of the following statements about conversion from Cartesian poses into joint coordinates is incorrect: Inverse kinematics are applied. Singularities and multiple solutions are considered. Forward kinematics are applied. It is a necessary step for kinematic control.

One of the following statements about the dynamic model of an arm-type robot is correct: Wrench applied at the end-effector may be considered through the Jacobian matrix. Friction depends on both the joint coordinates and velocities. The Coriolis and centripetal coupling matrix does not depend on the joint velocities. The inertia matrix depends on both the joint coordinates and accelerations.

One of the following statements about joint trajectory sampling is correct: It is not a necessary step for the kinematic control. Only positions are provided as set-points for the dynamic control. It is necessary to provide discrete-time references to the dynamic control. It is the first step of the kinematic control.

The friction term of the robot dynamic model. might become the least dominant force/torque for robots with reduction gearboxes. is linear with joint velocity. may include stiction and viscous friction. is reduced when the gear ratio increases.

One of the following statements about Cartesian trajectory sampling is correct: It is the last step of the kinematic control. The more the number of sampled points along the Cartesian trajectory, the lower the accuracy achieved when describing the desired trajectory. The number of sampled points along the Cartesian trajectory involves a trade-off between accuracy and computational cost. It is always a necessary step for kinematic control.

Concerning the computed torque model-based control,. All options are correct. It is made up of two control loops. The outer loop controls a linear and decoupled system. The inner loop linearizes and decouples the robot dynamics at every operating point.

Concerning independent control, ... All options are correct. The controller is designed considering that the dominant inertia and friction terms are those of the actuator. The non-diagonal terms of the inertia and Coriolis matrices are assumed to be negligible. The disturbance torque might be considered as negligible if the gear ratio is high enough.

The inertia matrix of the robot dynamic model ... sets an upper bound on joint acceleration for fixed maximum motor power. is antisymmetric. might be neglected for few degree-of-freedom robots. does not depend on the robot configuration.

One of the following statements about continuous trajectories is not correct: The path does not matter, but only the final destination point does. They are harder to compute than point-to-point trajectories. The robot may perform work along the trajectory. The robot is intended to describe a specific and a priori known Cartesian trajectory.

The Lagrangian energy-based method. has lower computational cost than the Newton-Euler's recursive algorithm. provides unstructured dynamic equations. makes use of all information contained in the homogeneous transformation matrices defined in the forward kinematics. is based on the inverse kinematics.

One of the following statements about the independent control is incorrect: The outer loop generates the reference for the position loop. The inner loop is responsible for tracking the velocity reference. It is made up of two control loops. The outer loop generates the reference for the velocity loop.

One of the following statements about the independent dynamic control is correct: Every joint is considered as an independent control system. It works with multiple-input-multiple-output (MIMO) systems rather than single-input-single-output (SISO) systems. It is based on the whole robot dynamic model. All control actions are computed together.

The rotational and linear dynamics of a mechanism. are all defined by the Euler's law. are all defined by the Newton's 2nd law. are computed from the inverse kinematics. are defined by both the Newton's 2nd law and the Euler's law.

One of the following criteria is not considered by kinematic control: Invested time to perform the task. Accuracy of the joint coordinate trajectories. Physical constraints of the actuators. Accuracy of the end-effector trajectory in the Cartesian space.

Concerning the Newton-Euler's recursive method ... all intermediate variables have a physical meaning. it provides an estimation of the friction term. it makes use of all information contained in the homogeneous transformation matrices defined in the forward kinematics. the final equations do not depend on the position of the link centres of mass.

One of the following statements about the dynamic model of an arm-type robot is correct: Friction depends on both the joint coordinates and velocities. The inertia matrix depends on both the joint coordinates and accelerations. Wrench applied at the end-effector may be considered through the Jacobian matrix. The Coriolis and centripetal coupling matrix does not depend on the joint velocities.

One of the following statements about the computed torque model-based control is incorrect: The joint error dynamics are completely decoupled thanks to the inner loop. The joint error dynamics are still coupled due to the non-diagonal inertia matrix. The joint error dynamics can be tuned through diagonal matrices. The joint error dynamics do not depend on the robot pose.

One of the following statements about conversion from Cartesian poses into joint coordinates is incorrect: Inverse kinematics are applied. Forward kinematics are applied. Singularities and multiple solutions are considered. It is a necessary step for kinematic control.

Concerning independent control,. It assumes no coupling between joints. It considers that inertia and Coriolis dynamic matrices can be assumed as diagonal. It only ensures a good performance if the gear ratio is high enough. All options are correct.

One of the following statements about the dynamic model of an induction DC motor is incorrect: The exerted torque is inversely proportional to the current. The electrical dynamics may be neglected with respect to the mechanical dynamics. The rotational speed depends on the input voltage. It must be considered when designing independent joint control.

One of the following statements about joint trajectory sampling is correct: It is not a necessary step for the kinematic control. Only positions are provided as set-points for the dynamic control. It is necessary to provide discrete-time references to the dynamic control. It is the first step of the kinematic control.

Transcripción Imagen 2 pregunta 1. One of the following criteria is not considered by kinematic control: Accuracy of the end-effector trajectory in the Cartesian space. Physical constraints of the actuators. Invested time to perform the task. Accuracy of the joint coordinate trajectories.