Transactions of the Canadian Society for Mechanical Engineering
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Volume 38 (2014), Issue 2
Guest Editorial: Special Issue on Mechanisms, Machines and Mechatronics
M. John D. Hayes, Ilian A. Bonev
A novel architecture for a parallel Schönflies motion generator was recently proposed, consisting of a CRRHHRRC linkage. The novelty of this architecture lies in its simplicity, as it comprises only two limbs, thereby forming a single-loop closed kinematic chain. Reported in this paper is a realization of this architecture, intended for the production of a proof-of-concept prototype. The realization includes an innovative actuator mechanism, which is based on two-degree-of-freedom cylindrical joints. Moreover, its moving plate is coupled to the two limbs by means of corresponding coaxial H pairs. The paper focuses on the kinematics and singularity analysis of this robot, intended for fast pick-and-place operations. The prototype is currently under development at McGill University's Centre for Intelligent Machines.
Analyse cinématique et dynamique d'un robot patineur
Louis-Thomas Schreiber, Clément Gosselin, Thierry Laliberté
Cet article présente un algorithme de planification de trajectoire pour un robot patineur entraîné par le mouvement relatif des patins par rapport au corps du robot. Les contraintes cinématiques non-holonomes associées au mouvement du robot sont d'abord établies. Ensuite, les équations du mouvement sont utilisées afin de calculer les efforts de frottement latéraux sur les patins. Un algorithme de planification de trajectoire basé sur des splines polynomiales de degré 7 est alors présenté. Un exemple de trajectoire est aussi montré afin de confirmer la capacité de l’algorithme à produire un mouvement continu et réaliste du robot. Finalement, un design conceptuel préliminaire du robot est présenté.
Structural optimisation of a force-torque sensor through its input-output relationship
Rachid Bekhti, Vincent Duchaine, Philippe Cardou
Autonomous Underwater Vehicles (AUVs) are presenting an ever expanding range of applications that enhance human capabilities and mitigate human risk. Development of a successful subsurface autonomous launch and recovery system would expand the functional use of AUVs in many fields, e.g., year-round Canadian Arctic exploration and sovereignty missions. This paper provides an overview of the design and dynamic modelling of two concept mechanisms being developed to recover AUVs to a slowly moving submerged submarine. Both have a serial R?R?P architecture; one is mechanically actuated while the second uses an actively pitched wing to indirectly provide motive force for the passive revolute joint. Dynamic models of both manipulators are developed. Although similar in architecture, several extensions are required to accurately predict the non-linear dynamics provided by the wing. High speed actuation of the devices is required to compensate for relative trajectory errors between the submarine and AUV during significant sea states in littoral waters. Alterations to the recursive Newton–Euler method to include hydrodynamic and additional inertial forces present in water are explained. Results of some initial modelling are presented.
Dynamics of two active autonomous dock mechanisms for AUV recovery
Jason Currie, Colin B. Gillis, Juan A. Carretero, Rickey Dubay, Tiger Jeans, George D. Watt
An optimization technique based on Mixed Integer Linear Programming (MILP) was applied to a hospital located in Sudbury, Ontario, Canada. The energy services included electricity, heat, steam, and coolth. Different options for the system’s operation were also considered in the optimization procedure. The optimization model determines the optimal configuration of the polygeneration system and the best operational strategy. The primary objective for optimization is to minimize the hospital’s annual energy costs. This objective can be achieved by consuming low-priced natural gas, operating the gas engines at full load to generate electricity, and selling all of this electricity into the provincial grid, which ensures the hospital’s eligibility to receive government payments for cogeneration.
Kinematic analyses of a new medical robot for 3D vascular ultrasound examination
Longfei Zhao, Andy Kar Wah Yen, Jonathan Coulombe, Pascal Bigras, Ilian A. Bonev
Peripheral artery disease (PAD) is a common vascular disease which can have serious consequences for older people. Owing to the complexity of the vessels in the lower limbs, current PAD medical robots are not desirable to diagnose PAD in this area. The kinematic model of a novel six-axis serial-parallel robot for 3D vascular ultrasound examination of the lower limbs is presented in this paper. The prototype of the robot is described, and then the direct and inverse kinematic problems are solved in closed form.
Saturated proportional derivative control of a single-link flexible-joint manipulator
Ryan James Caverly, David Evan Zlotnik, James Richard Forbes
This paper considers the control of a single-link flexible-joint robot manipulator subject to actuator saturation. Alternative controllers are proposed and compared to one found in literature. In particular, a controller with proportional and derivative components is guaranteed to provide a total torque less than a chosen value, thereby disallowing actuator saturation. It is shown that an equilibrium point of the closed-loop system is asymptotically stable. Additionally, it is shown that the controllers are robust to modelling errors. Finally, this paper presents simulation results demonstrating the performance of the proposed control architecture.
Atlas motion platform Mecanum wheel Jacobian in the velocity and static force domains
Jonathan J. Plumpton, M. John D. Hayes, Robert G. Langlois, Bruce V. Burlton
Conventional training simulators commonly use the hexapod configuration to provide motion cues. While widely used, studies have shown that hexapods are incapable of producing the range of motion required to achieve high fidelity simulation required in many applications. Atlas is a six degree of freedom vehicle operating training simulator motion platform where orienting is decoupled from positioning, and unbounded rotation is possible about any axis. Angular displacements are achieved by manipulating the cockpit contained in a 2.9 metre (9.5 foot) diameter sphere with three Mecanum wheel actuators. The angular velocity Jacobian, Jω, maps the desired angular velocity of the sphere to the required speeds of the three Mecanum wheels, while the static force Jacobian, Jτ, maps the static moment vector required to statically orient the sphere to the static torques required by the three Mecanum wheels. In this paper, the two Jacobians are derived independently, and it is confirmed that Jω = JτT, as it must. The implications on the required normal forces at the interface between the sphere and three Mecanum wheel contact patches are discussed.
Dynamic modelling, estimation, and control for precision pointing of an atmospheric balloon platform
David Evan Zlotnik, James Richard Forbes
In this paper we consider the dynamic modelling, estimation and control of an atmospheric balloon platform. The platform is modelled as a rigid body constrained to move with a three dimensional pendulum. We investigate the dynamics of the system and derive the equations of motion from first principles. A nonlinear estimator that evolves on the special orthogonal group of rigid-body rotations, denoted SO(3), is implemented and used in conjunction with a proportional derivative (PD) compensator to control the yaw angle of the platform. A simulation is conducted, and the results demonstrate successful estimation and yaw control.
Full journal title: Transactions of the Canadian Society for Mechanical Engineering
Abreviated journal title: Trans. Can. Soc. Mech. Eng.
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