Design of a novel inchworm in-pipe robot based on cam-linkage mechanism

This paper presents a novel double-direction inchworm in-pipe robot, called the Cam-Linkage Robot (CLR), used to carry sensors and instruments to perform inspection and cleaning jobs inside pipelines. The prototype has been developed to improve the driving ability and reduce the difficulty of control. CLR is suitable for pipe diameters from 360 mm to 400 mm due to its functions of manual adjustment and automatic adaptation. The structure of CLR was presented and some critical design issues on the principle of cam-linkage mechanism were discussed. Based on cam-linkage mechanism, CLR could press the wall actively and creep in two directions via only one motor, so this research has broken the limitation that traditional active wall-press robot needs more than one actuator. The cam pressure angle could be reduced to 0, and the propulsion ability was almost not weakened by the support motion at the stable support stage. Finally, experiments were conducted to validate the locomotion principle and the effectiveness of CLR.

Modeling Movement of Supports of Walking Machines with Dynamic Stability by Using a Stand

Introduction. Walking machines have been interesting for decades. Modern technologies make it possible to create new designs with digital control. Creating software that allows a walking machine to move independently is a difficult task. Walking machine onboard computer needs to process data from sensors in real time. The article demonstrates design and algorithms used to control the motion of an experimental walking machine. Materials and Methods. To simulate the motion of a walking machine and experimental studies, a stand replicating all the electronic systems of the machine was made. The order of rearrangement of the supports during the motion and the trajectory of the support movement are shown. The design of sensors and their principle of operation are considered. The simulation bench with a description of its electronic components is demonstrated. Results. The optimal parameters of the support motion are determined. A cyclic algorithm for specifying the motion of a support along a trajectory consisting of rectilinear segments is described. The problem of synchronization of motion of a set of supports using multithreaded asynchronous programming adapted for multidimensional processors has been solved. The process of lowering the support to the surface and the response of the cyclic algorithm to changes in the shock and load sensor readings are simulated. Discussion and Conclusion. An algorithm for propulsion with reaction to changes in sensor readings has been developed. The conducted research allowed us to obtain an optimal algorithmic model of motion, to which it is easy to add new reactions of the automatic motion control system based on sensor readings.

Controlling a Variable-Length Exoskeleton Link

The aim of the study is to develop a spatial electromechanical model of a variable-length link for use in telescopic manipulators, anthropomorphic robots, exoskeletons, and in studying the human musculoskeletal system. The proposed link model has two massive absolutely solid sections at the ends and a weightless section of variable length located between them. The study was carried out using the methods of theoretical mechanics, electromechanics, mathematical modeling, engineering design, numerical methods for solving systems of ordinary differential equations, control theory, nonlinear dynamics, experimental methods, and empirical data on the biomechanical properties of the human musculoskeletal system. The reliability of the obtained results is substantiated by a rigorous use of the above-mentioned methods. As a result of the study, a system of Lagrange-Maxwell differential equations was written, and an electromechanical model of an anthropomorphic system was developed in the Matlab Simulink software package. With the specified geometric and inertial parameters of a variable-length link corresponding to an average person's leg lower part and the time corresponding to the single-support motion phase, the electric motors and reducing gears implementing the human musculoskeletal system link's biomechanical motion fragment are selected. All of the selected motors have a sufficient operating parameters margin. The trajectories of all generalized coordinates along which the anthropomorphic system performs its necessary motion are determined. The mechanism load diagrams are obtained. The control system for the motors is synthesized, and the positioning error is evaluated. The novelty of the approach is that the newly developed electromechanical models of controlled variable-length links have a wide range of applying the obtained results and can be used in designing anthropomorphic robots and comfortable new-generation exoskeletons. Thus, the electromechanical model of a variable-length link with the parameters corresponding to the average person's leg lower part has been developed. The electric drives and transmissions able to implement a motion close to the anthropomorphic one have been selected; its implementation has been demonstrated, and the numerical calculation results are given.

ENERGY BALANCE DURING FREIGHT ELECTRIC LOCOMOTIVE OPERATION

The purpose of this work consists in obtaining power indices of a freight electric locomotive at the specified schedule of motion, but at different laws of speed changes and on different track profiles. CAD methods are used, at that, the further comparison of the results obtained with the records of the locomotive crew recorder has shown an actually complete coincidence. As expected, a minimum work performed for a train hauling is achieved in an ideal case – at the motion without stops at a constant speed on a straight horizontal track. When moving along an actual profiled track a work performed for hauling changes by a difference of potential energy of gravity in the initial and end points. Often accelerations and slowdowns result in the work increase for hauling, for that there are obtained quantity values. In order to avoid excess power waste it is necessary to move possibly without sharp accelerations and hard braking. To support motion uniformity it is expedient to use a speed controller. There are obtained the values of a specific work for train hauling in different cases which define limits for a purpose index on the

Study of the characteristics of soil surfaces as roads for agricultural robotic complexes

The article is devoted to the study of using mobile robotic systems in agriculture. It is shown that it is necessary to know the physical and mechanical characteristics of the main support motion surfaces to calculate the mobility and efficiency of these complexes. This will allow calculating the movement resistance and traction force, and as a result, choosing the best appliance design for these conditions. Typical areas of agricultural land near the village of Belka in the Knyaginino district of the Nizhny Novgorod region were analyzed. More than 200 measurements were made. The dependencies for calculating the main soil parameters are described. It is obtained that the average values of the soil parameters change within the following limits: the deformation modulus is 15.5-23 N/cm2, the specific soil adhesion is 13.9-16.7 kPa, the internal friction angle is 14.8-16.4 degrees, the density is 1.09-1.14 g/cm3, the soil moisture is 035-16, 9%.

RIGID AND NON-RIGID KINEMATIC EXCITATION FOR MULTIPLY-SUPPORTED SYSTEM: ONCE MORE ABOUT THE CONTRIBUTION OF DAMPING TO THE DYNAMIC LOADS IN SEISMIC ANALYSIS

Development of linear equations of motion for seismic analysis is discussed in the paper. The paper continues the discussion: the author does not agree with colleagues putting damping matrix into the right-hand part of the equation of motion describing dynamic loads. This disagreement refers to the most popular case of “rigid” motion of multiple supports. In this paper the author follows the logic of general “non-rigid” support motion and points out a step in the equation development when the transition to “rigid” support motion (as a particular case of “non-rigid” motion) is spoiled by the opponents. In the author’s opinion, the mistake is in the implementation of the Rayleigh damping model for the right-hand part of the equation. This is in the contradiction with physical logic, as damping in the Rayleigh model is not really “internal”: due to the participation of mass matrix it works on rigid displacements, which is impossible for internal damping.

Motion Processing in Primates

The ability to see motion is critical to survival in a dynamic world. Decades of physiological research have established that motion perception is a distinct sub-modality of vision supported by a network of specialized structures in the nervous system. These structures are arranged hierarchically according to the spatial scale of the calculations they perform, with more local operations preceding those that are more global. The different operations serve distinct purposes, from the interception of small moving objects to the calculation of self-motion from image motion spanning the entire visual field. Each cortical area in the hierarchy has an independent representation of visual motion. These representations, together with computational accounts of their roles, provide clues to the functions of each area. Comparisons between neural activity in these areas and psychophysical performance can identify which representations are sufficient to support motion perception. Experimental manipulation of this activity can also define which areas are necessary for motion-dependent behaviors like self-motion guidance.