Influence of lntermittency and Synergy on Grasping

Motor Control ◽  
1999 ◽  
Vol 3 (3) ◽  
pp. 280-284 ◽  
Author(s):  
Peter D. Neilson
Keyword(s):  
Trajectory Planning ◽  
Movement Control ◽  
Human Movement ◽  
Optimization Criterion ◽  
Coordinate Space ◽  
Processing Load ◽  
Minimum Jerk

This commentary firstly supports Smeets and Brenner in their choice of a kinematic trajectory, submitting that the challenge posed by the rival torque-change formulation is resolved by consideration of intermittency in human movement control. Second, it examines the choice of optimization criterion for trajectory planning, arguing in favor of minimum acceleration rather than minimum jerk. Third, using the notion of optimized trajectories in task-dependent coordinate space together with synergy generation, it suggests a formulation that reduces the processing load entailed in Smeets and Brenner's proposal of individual trajectories for each digit.

Minimum Jerk Trajectory Planning of PUMA560 with Intelligent Computation using ANN

2021 ◽  
Author(s):  
M Aruna Devi ◽  
C P S Prakash ◽  
Praveen D Jadhav ◽  
Prajwal S Hebbar ◽  
Mohammed Mohsin ◽  
...  
Keyword(s):  
Trajectory Planning ◽  
Minimum Jerk

scholarly journals Trajectory planning of multiple coordinating robots using genetic algorithms

Robotica ◽  
1996 ◽  
Vol 14 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Shudong Sun ◽  
A.S. Morris ◽  
A.M.S. Zalzala
Keyword(s):  
Genetic Algorithms ◽  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Coordinate Space ◽  
Object A ◽  
Dynamic Constraints ◽  
Order Polynomial ◽  
Cartesian Coordinate ◽  
Three Degrees Of Freedom

SUMMARYThe paper focuses on the problem of trajectory planning of multiple coordinating robots. When multiple robots collaborate to manipulate one object, a redundant system is formed. There are a number of trajectories that the system can follow. These can be described in Cartesian coordinate space by an nth order polynomial. This paper presents an optimisation method based on the Genetic Algorithms (GAs) which chooses the parameters of the polynomial, such that the execution time and the drive torques for the robot joints are minimized. With the robot's dynamic constraints taken into account, the pitimised trajectories are realisable. A case study with two planar-moving robots, each having three degrees of freedom, shows that the method is effective.

scholarly journals Minimum-jerk trajectory planning pertaining to a translational 3-degree-of-freedom parallel manipulator through piecewise quintic polynomials interpolation

2020 ◽  
Vol 12 (3) ◽  
pp. 168781402091366 ◽  
Author(s):  
Song Lu ◽  
Bingxiao Ding ◽  
Yangmin Li
Keyword(s):  
Trajectory Planning ◽  
Virtual Work ◽  
Angular Position ◽  
Programming Algorithm ◽  
Planning Problem ◽  
Typical Application ◽  
Parallel Kinematic Manipulator ◽  
Minimum Jerk ◽  
Planning Approach ◽  
Parallel Kinematic

This article aims to present a minimum-jerk trajectory planning approach to address the smooth trajectory generation problem of 3-prismatic-universal-universal translational parallel kinematic manipulator. First, comprehensive kinematics and dynamics characteristics of this 3-prismatic-universal-universal parallel kinematic manipulator are analyzed by virtue of the accepted link Jacobian matrices and proverbial virtual work principle. To satisfy indispensable continuity and smoothness requirements, the discretized piecewise quintic polynomials are employed to interpolate the sequence of joints’ angular position knots which are transformed from these predefined via-points in Cartesian space. Furthermore, the trajectory planning problem is directly converted into a constrained nonlinear multi-variables optimization problem of which objective function is to minimize the maximum of the joints’ angular jerk throughout the whole trajectory. Finally, two typical application simulations using the reliable sequential quadratic programming algorithm demonstrate that this proposed minimum-jerk trajectory planning approach is of explicit feasibility and appreciable effectiveness.

The trajectory of human wrist movements

1988 ◽  
Vol 59 (6) ◽  
pp. 1814-1830 ◽  
Author(s):  
R. B. Stein ◽  
F. W. Cody ◽  
C. Capaday
Keyword(s):  
Nervous System ◽  
Energy Consumption ◽  
Human Movement ◽  
Normal Subjects ◽  
Kinematic Variable ◽  
Wrist Flexion ◽  
Movement Trajectories ◽  
Minimum Jerk ◽  
Inertial Loading ◽  
Third Derivative

1. To determine the form of human movement trajectories and the factors that determine this form, normal subjects performed wrist flexion movements against various elastic, viscous, and inertial loads. The subjects were instructed with visual and auditory feedback to make a movement of prescribed amplitude in a present period of time, but were free to choose any trajectory that fulfilled these constraints. 2. The trajectories were examined critically to determine if they corresponded to those which would minimize the root mean square (RMS) value of some kinematic variable or of energy consumption. The data agreed better with the trajectory that minimized the RMS value of jerk (the third derivative of length) than that of acceleration. However, systematic deviations from the minimum jerk predictions were consistently observed whenever movements were made against elastic and viscous loads. 3. Improved agreement could generally be obtained by assuming that the velocity profile varied according to a normal (Gaussian) curve. We conclude that minimization of jerk is not a general principle used by the nervous system in organizing voluntary movements, although movements may approach the predicted form, particularly under inertial loading conditions. 4. The EMG of the agonist muscles consisted of relatively simple waveforms containing ramplike increases and approximately exponential decays. The form of the movements could often be predicted quite well by using the EMG as an input to a linear second-order model of the muscle plus load. Rather than rigorously minimizing a kinematic variable or energy consumption, the nervous system may generate simple waveforms and adjust the parameters of these waveforms by trial and error until a trajectory is achieved that meets the requirements for a given load.

Unique features of human movement control predicted by the leading joint hypothesis

2012 ◽  
Vol 35 (4) ◽  
pp. 223-224
Author(s):  
Natalia Dounskaia
Keyword(s):  
Motor Control ◽  
Cognitive Processes ◽  
Tool Use ◽  
Movement Control ◽  
Human Movement ◽  
Limb Movements ◽  
Human Limb

AbstractVaesen suggests that motor control is not among the primary origins of the uniqueness of human tool use. However, recent findings show that cognitive processes involved in control of human limb movements may be much more sophisticated than it was believed previously. The sophistication of movement control may substantially contribute to the uniqueness of humans in tool use.

Minimum jerk for trajectory planning and control

Robotica ◽  
1994 ◽  
Vol 12 (2) ◽  
pp. 109-113 ◽  
Author(s):  
K.J. Kyriakopoulos ◽  
G.N. Saridis
Keyword(s):  
Trajectory Planning ◽  
Tracking Control ◽  
Optimization Problem ◽  
Control Algorithms ◽  
Planning Problem ◽  
Cartesian Space ◽  
Planning And Control ◽  
Minimum Jerk ◽  
And Control ◽  
Trajectory Planning And Control

SUMMARYIt has been experimentally verified that the jerk of the desired trajectory adversely affects the performance of the tracking control algorithms for robotic manipulators. In this paper, we investigate the reasons behind this effect, and state the trajectory planning problem as an optimization problem that minimizes a norm of joint jerk over a prespecified Cartesian space trajectory. The necessary conditions are derived and a numerical algorithm is presented.

Choosing the Right “Bit Pad”: Human Factors Aspects of Digitizing Tablet Size

1982 ◽  
Vol 26 (7) ◽  
pp. 615-615
Author(s):  
James L. Knight
Keyword(s):  
Computer Graphics ◽  
Task Analysis ◽  
Movement Control ◽  
Human Movement ◽  
Optimum Size ◽  
Wide Range ◽  
The Right ◽  
Parameter Values ◽  
Selection Of ◽  
Digitizing Tablet

Entry of non-alphanumeric information into computer graphics systems is frequently accomplished by moving a drawing implement over the surface of a digitizing tablet. These tablets are commercially available in a wide range of sizes. Therefore, an important question from both ergonomic and economic standpoints concerns the optimum size for the digitizing tablet. To answer this question, models of human movement control were applied to the graphic operator's task. An experiment was conducted to obtain appropriate model parameter values and to empirically evaluate the resulting predictions of the generated models. A combination of task analysis and movement control modelling thus allowed selection of an optimum digitizing tablet size for a range of computer-graphics entry tasks. Details and results of this methodology will be presented.

Orientation and Movement in Unusual Force Environments

1993 ◽  
Vol 4 (3) ◽  
pp. 134-142 ◽  
Author(s):  
James R. Lackner
Keyword(s):  
Present Article ◽  
Movement Control ◽  
Human Movement ◽  
Space Mission ◽  
Artificial Gravity ◽  
Adaptive Changes ◽  
Earth Gravity ◽  
Long Duration ◽  
Wide Range ◽  
Manned Space

A manned space mission to Mars might take as long as 1 year each way. Consequently, artificial gravity is being considered as a way of preventing the debilitating effects of long-duration exposure to microgravity on the human hotly. The present article discusses some of the problems associated with adapting to the rotation levels that might be used to generate artificial gravity. It also describes how exposure to background-force levels greater or less than the 1-G force of Earth gravity affects orientation and movement control. The primary emphasis of the article is that human movement and orientation control are dynamically adapted to the 1-G force background of Earth and that accommodation to altered force levels or to rotating environments requires a wide range of adaptive changes.

scholarly journals Motor cortical beta transients delay movement initiation and track errors

2018 ◽  
Author(s):  
Simon Little ◽  
James Bonaiuto ◽  
Gareth Barnes ◽  
Sven Bestmann
Keyword(s):  
Movement Control ◽  
Monitoring And Evaluation ◽  
Human Movement ◽  
High Amplitude ◽  
Burst Activity ◽  
Beta Activity ◽  
Movement Initiation ◽  
Before And After ◽  
Motor Cortical ◽  
Spatio Temporal

ABSTRACTMotor cortical activity in the beta range (13-30 Hz) is a hallmark signature of healthy and pathological movement, but its behavioural relevance remains unclear. Recent work in primates and human sensory cortex suggests that sustained oscillatory beta activity observed on average, may arise from the summation of underlying short-lasting, high-amplitude bursts of activity. Classical human movement-related event-related beta desynchronisation (ERD) and synchronization (ERS) may thus provide insufficient, non-dynamic, summaries of underlying focal spatio-temporal burst activity, limiting insight into their functional role during healthy and pathological movement.Here we directly investigate this transient beta burst activity and its putative behavioural relevance for movement control, using high-precision magnetoencephalography (MEG). We quantified the subject-specific (n=8), trial-wise (n>12,000) dynamics of beta bursts, before and after movement. We show that beta activity on individual trials is dominated by high amplitude, short lasting bursts. While average beta changes generally manifest as bilaterally distributed activity (FWHM = 25mm), individual bursts are spatially more focal (FWHM = 6 mm), sporadic (1.3 −1.5/s), and transient (mean: 96 ms).Prior to movement (the period of the classical ERD), the timing of the last pre-movement burst predicts movement onset, suggesting a role in the specification of the goal of movement. After movement (the period of the classical ERS), the first beta burst is delayed by ~100ms after a response error occurs, intimating a role in error monitoring and evaluation.Movement-related beta activity is therefore dominated by a spatially dispersed summation of short lasting, sporadic and focal bursts. Movement-related beta bursts coordinate the retrieval and updating of movement goals in the pre- and post-movement periods, respectively.

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