This book presents the basics of an exciting new field. It is exciting because it extends our age... more This book presents the basics of an exciting new field. It is exciting because it extends our age-old fascination with tools and machines into experimental areas far beyond mere mechanics and because of the many ways it promises to affect our lives. Certainly, it is new, since the development of robots has taken place only in very recent times.
Some manipulability measures have been used in previous works to provide a quantification of the ... more Some manipulability measures have been used in previous works to provide a quantification of the manipulator's closeness to singularity. This paper utilizes the manipulability measure of a manipulator and proposes a manipulability measure of an object grasped by a multi-fingered hand. This measure is used for finding, in the stable grasp space, optimal contact points between the fingers and an object, and avoiding singular configurations during motion. A manipulability mapping algorithm, applied to the four-fingered Utah/MIT hand, was developed for finding hand low manipulability envelopes and restricted directions of motion. The results of graphical simulation are presented.
The mechanical arm is the means used by the robot to move its end effector to the desired points,... more The mechanical arm is the means used by the robot to move its end effector to the desired points, in a manner similar to that of the human arm. Since most of today’s robots are stationary, the arm is generally the only part of the robot that moves. In the future, with mobile robots coming into use, it is possible that additional parts — such as artificial legs — will be called upon to execute motions. This will require the use of mechanical legs (or wheels), additional motors, and the robot “brain” capable of controlling the motion of the mechanical legs as well as that of the arm (arms).
The energy consumption of worm robots is composed of three parts: heat losses in the motors, inte... more The energy consumption of worm robots is composed of three parts: heat losses in the motors, internal friction losses of the worm device and mechanical energy locomotion requirements which we refer to as the cost of transport (COT). The COT, which is the main focus of this paper, is composed of work against two types of external factors: (i) the resisting forces, such as weight, tether force, or fluid drag for robots navigating inside wet environments and (ii) sliding friction forces that may result from sliding either forward or backward. In a previous work, we determined the mechanical energy requirement of worm robot locomotion over compliant surfaces, independently of the efficiency of the worm device. Analytical results were obtained by summing up the external work done on the robot and alternatively, by integrating the actuator forces over the actuator motions. In this paper, we present experimental results for an earthworm robot fitted with compliant contacts and these are post-processed to estimate the energy expenditure of the device. The results show that due to compliance, the COT of our device is increased by up to four-fold compared to theoretical predictions for rigid-contact worm-like locomotion.
A new structure of a six degrees-of-freedom robot is described in this paper. The robot presents ... more A new structure of a six degrees-of-freedom robot is described in this paper. The robot presents two new features: three inflatable links that constitute the robot structure and parallel robot architecture with large workspace. These features result in a lightweight and easy to deploy robot. The structure, kinematics and path planning of the experimental robot are presented.
The construction of a new type of a six-degrees-of-freedom parallel robot is presented in this pa... more The construction of a new type of a six-degrees-of-freedom parallel robot is presented in this paper. Coordinated motion of three planar motors, connected to three fixed-length links, produces a six-degrees-of-freedom motion of an output link. Its extremely simple design along with much larger work volume make this high performance-to-simplicity ratio robot very attractive.
<jats:title>Abstract</jats:title> <jats:p>Kinematicians have used dual numbers ... more <jats:title>Abstract</jats:title> <jats:p>Kinematicians have used dual numbers to obtain rigid body kinematics in a compact three-dimensional form by substituting dual for real numbers in the equation of rotational motion. No such simple relation, known as 'principle of transference', existed however, for dynamics. The commonly used inertia binor by which dual momentum is calculated, raises the dual dynamic equations to six dimensions. In fact, the inertia binor does not act on the dual vector as a whole, but rather on its real and dual parts as two distinct real vectors.</jats:p> <jats:p>The recently introduced dual mass operator can serve as the missing link between the dual kinematic and the dual dynamic equations. It gives the mass a dual property which has a complementary sense of Clifford's dual unit, namely, it reduces a motor to a rotor proportional to the vector part of the motor. With this definition of mass, the same equation of momentum and its time derivative, which holds for a linear motion, holds for both linear and angular motion of a rigid body if dual force, dual velocity, and dual inertia replace their real counterparts.</jats:p> <jats:p>Application of the dual inertia operator and motor transformation rule permits derivation of an explicit dynamic algorithm of a serial manipulator which has several advantages over the more conventional Newton-Euler and Lagrange formulations. Firstly, all the expressions of this algorithm are explicit parts of the dual transformation matrices and the constant link-attached inertia parameters. Secondly, this algorithm is an explicit, not a recursive one and does not require derivative of any one of its terms. It rather gives all coefficients of the dynamic equations in a simple and compact form of determinants and vector scalar product.</jats:p>
This paper introduces for the first time, the Lagrange's dynamic equations in dual number qua... more This paper introduces for the first time, the Lagrange's dynamic equations in dual number quaternion form. Additionally, Rayleigh's dissipation function in dual quaternion form is introduced here allowing for the accounting of dissipative (non-conservative) forces such as motion through a viscous fluid, friction, and spring damping force. As an example, dual quaternions are used here to derive the Lagrange dynamic equations of a robot manipulator.
This book presents the basics of an exciting new field. It is exciting because it extends our age... more This book presents the basics of an exciting new field. It is exciting because it extends our age-old fascination with tools and machines into experimental areas far beyond mere mechanics and because of the many ways it promises to affect our lives. Certainly, it is new, since the development of robots has taken place only in very recent times.
Some manipulability measures have been used in previous works to provide a quantification of the ... more Some manipulability measures have been used in previous works to provide a quantification of the manipulator's closeness to singularity. This paper utilizes the manipulability measure of a manipulator and proposes a manipulability measure of an object grasped by a multi-fingered hand. This measure is used for finding, in the stable grasp space, optimal contact points between the fingers and an object, and avoiding singular configurations during motion. A manipulability mapping algorithm, applied to the four-fingered Utah/MIT hand, was developed for finding hand low manipulability envelopes and restricted directions of motion. The results of graphical simulation are presented.
The mechanical arm is the means used by the robot to move its end effector to the desired points,... more The mechanical arm is the means used by the robot to move its end effector to the desired points, in a manner similar to that of the human arm. Since most of today’s robots are stationary, the arm is generally the only part of the robot that moves. In the future, with mobile robots coming into use, it is possible that additional parts — such as artificial legs — will be called upon to execute motions. This will require the use of mechanical legs (or wheels), additional motors, and the robot “brain” capable of controlling the motion of the mechanical legs as well as that of the arm (arms).
The energy consumption of worm robots is composed of three parts: heat losses in the motors, inte... more The energy consumption of worm robots is composed of three parts: heat losses in the motors, internal friction losses of the worm device and mechanical energy locomotion requirements which we refer to as the cost of transport (COT). The COT, which is the main focus of this paper, is composed of work against two types of external factors: (i) the resisting forces, such as weight, tether force, or fluid drag for robots navigating inside wet environments and (ii) sliding friction forces that may result from sliding either forward or backward. In a previous work, we determined the mechanical energy requirement of worm robot locomotion over compliant surfaces, independently of the efficiency of the worm device. Analytical results were obtained by summing up the external work done on the robot and alternatively, by integrating the actuator forces over the actuator motions. In this paper, we present experimental results for an earthworm robot fitted with compliant contacts and these are post-processed to estimate the energy expenditure of the device. The results show that due to compliance, the COT of our device is increased by up to four-fold compared to theoretical predictions for rigid-contact worm-like locomotion.
A new structure of a six degrees-of-freedom robot is described in this paper. The robot presents ... more A new structure of a six degrees-of-freedom robot is described in this paper. The robot presents two new features: three inflatable links that constitute the robot structure and parallel robot architecture with large workspace. These features result in a lightweight and easy to deploy robot. The structure, kinematics and path planning of the experimental robot are presented.
The construction of a new type of a six-degrees-of-freedom parallel robot is presented in this pa... more The construction of a new type of a six-degrees-of-freedom parallel robot is presented in this paper. Coordinated motion of three planar motors, connected to three fixed-length links, produces a six-degrees-of-freedom motion of an output link. Its extremely simple design along with much larger work volume make this high performance-to-simplicity ratio robot very attractive.
<jats:title>Abstract</jats:title> <jats:p>Kinematicians have used dual numbers ... more <jats:title>Abstract</jats:title> <jats:p>Kinematicians have used dual numbers to obtain rigid body kinematics in a compact three-dimensional form by substituting dual for real numbers in the equation of rotational motion. No such simple relation, known as 'principle of transference', existed however, for dynamics. The commonly used inertia binor by which dual momentum is calculated, raises the dual dynamic equations to six dimensions. In fact, the inertia binor does not act on the dual vector as a whole, but rather on its real and dual parts as two distinct real vectors.</jats:p> <jats:p>The recently introduced dual mass operator can serve as the missing link between the dual kinematic and the dual dynamic equations. It gives the mass a dual property which has a complementary sense of Clifford's dual unit, namely, it reduces a motor to a rotor proportional to the vector part of the motor. With this definition of mass, the same equation of momentum and its time derivative, which holds for a linear motion, holds for both linear and angular motion of a rigid body if dual force, dual velocity, and dual inertia replace their real counterparts.</jats:p> <jats:p>Application of the dual inertia operator and motor transformation rule permits derivation of an explicit dynamic algorithm of a serial manipulator which has several advantages over the more conventional Newton-Euler and Lagrange formulations. Firstly, all the expressions of this algorithm are explicit parts of the dual transformation matrices and the constant link-attached inertia parameters. Secondly, this algorithm is an explicit, not a recursive one and does not require derivative of any one of its terms. It rather gives all coefficients of the dynamic equations in a simple and compact form of determinants and vector scalar product.</jats:p>
This paper introduces for the first time, the Lagrange's dynamic equations in dual number qua... more This paper introduces for the first time, the Lagrange's dynamic equations in dual number quaternion form. Additionally, Rayleigh's dissipation function in dual quaternion form is introduced here allowing for the accounting of dissipative (non-conservative) forces such as motion through a viscous fluid, friction, and spring damping force. As an example, dual quaternions are used here to derive the Lagrange dynamic equations of a robot manipulator.
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