Zhenishbek Zhakypov

The design and control of the multi-modal locomotion origami robot, Tribot

Origami robots (Robogamis) use architecture to strategically activate different sets and sequence of actuators to achieve large variety of reconfigurable forms. Tribot is a unique mobile origami robot that can simultaneously choose between two modes of locomotion: jumping and crawling. When assembled, Tribot measures 64 × 34 × 20 mm3, weighs 4 g, crawls at 17% of its body length per gait cycle and jumps seven times its height repeatedly without needing to be reset. To optimize the practicality of the nominally 2D design, we made two different approaches to build the prototypes. For one of them, we used the “traditional”, monolithic, layer-by-layer robogami fabrication method and the second, we printed out most parts using a multi-material 3D printer. By showing the performance of two prototypes side-by-side, we show that with the 3D printer, we can minimize the number of functional layers and reduce the fabrication time. The embedded sensors allow Tribots crawling gait pattern and jumping height to be modulated with a closed loop control. We compare the expected gait step size and displacement to that of the presented prototype while describing the design and control parameters to achieve the experimental results. We also illustrated the preliminary graphical design tool platform developed to optimize the next design iteration of Tribot.

Adaptive control of piezoelectric walker actuator

This work focuses on the design of adaptive controller for high precision positioning purposes using PiezoLegs actuator. Actuator is driven with the set of periodical sine shaped voltages with known frequency, amplitude and phase shift between the phases. Clear relationships between the amplitude and phase shifts between the phases and actuator step size have been established. Based on these relationships adaptive controller has been designed. Controller is a linear, cascaded type of feedback controller that uses position feedback from an encoder. Based on the information of the absolute error controller performs the adaptive step size modulation by changing amplitude or phase shift of the driving voltages. Proposed algorithm is validated experimentally. Experimental results show satisfactory level performance, controller achieves fast settling time, no overshoot response and high accuracy of positioning with small steady state errors.

Galvanometric optical laser beam steering system for microfactory application

This article presents a kinematic model and control of a galvanometric laser beam steering system for high precision marking, welding or soldering applications as a microfactory module. Galvo systems are capable of scanning laser beam with relatively high frequencies that makes them suitable for fast processing applications. For the sake of flexibility and ease of use 2D reference shapes to be processed are provided as CAD drawings. Drawings are parsed and interpolated to x - y reference data points on MATLAB then stored as arrays in C code. C header file is further included as reference data points to be used by the system. Theoretical kinematic model of the system is derived and model parameters are tuned for practical implementation and validated with respect to measured positions on rotation space with optical position sensor and image field with position sensitive device. Machining with material removal requires high power laser to be employed that makes position measurement on image field unfeasible. Therefore for closed loop applications optical position sensor embedded in galvo motors is used for position feedback. Since the model approved to be approximately linear in the range of interest by simulations, a PI controller is used for precise positioning of the galvo motors. Experimental results for tracking circular and rectangular shape references are proved to be precise with errors of less than 2%.

Design Methodology for Constructing Multimaterial Origami Robots and Machines

Robotic origami allows rapid prototyping of intelligent robots and machines constructed from thin sheets of functional materials. Multimaterial-based design freedom of origami robots creates functional versatility; however, the design parameters pose challenges in their mechanical layout and fabrication. While the conventional robot design follows a coherent and well-established design process, the construction of origami robots requires close study of their three-dimensional (3-D) and two-dimensional (2-D) geometries, compliant mechanisms, functional material specific components, and 2-D fabrication methods. In this paper, we report a systematic design methodology for building origami-inspired machines and robots based on these four essential design features. We provide their comprehensive formulation, comparing them to conventional robots and highlighting design challenges as well as potentials. We demonstrate the applicability of our procedure to the majority of origami robots in the literature and also validate it by designing a centimeter-scale jumping and crawling origami robot, Tribot, as a showcase. The 6-g Tribot crawls with fixed steps in a closed loop, adjusts its vertical jumping height by power modulation, and overcomes obstacles of 45-mm height by side jumps. This paper advances the design and fabrication methodology of origami robots, with customizable functionality from the ground-up.

Desktop microfactory for high precision assembly and machining

This work presents a modular and reconfigurable desktop microfactory for high precision machining and assembly of micro mechanical parts. Miniature factory is inspired by the downsizing trend of the production tools. The system is constructed based on primary functional and performance requirements such as miniature size, operation with sub-millimeter precision, modular and reconfigurable structure, parallel processing capability, ease of transportation and integration. Proposed miniature factory consists of several functional modules such as two parallel kinematic robots for manipulation and assembly, galvanometric laser beam scanning system for micromachining, camera system for inspection, and a rotational conveyor system for sample part delivery. The overall mechanical structure of the proposed microfactory facilitates modularity and reconfigurability, parallel processing, flexible rearrangement of the layout, and ease of assembly and disassembly of the whole structure. Experiments involve various tasks within a single process such as pick-place of the 3 mm diameter metallic ball, marking a 2D sub-millimeter image on the ball surface with high power laser, and inspection along with verification of the image by means of microscopic camera. Results have shown the possibility of implementation of the desktop microfactory concept for machining and assembly of tiny mechanical parts with microprecision.

An Origami-Inspired Reconfigurable Suction Gripper for Picking Objects with Variable Shape and Size

Gripper adaptability to handle objects of different shape and size brings high flexibility to manipulation. Gripping flat, round, or narrow objects poses challenges to even the most sophisticated robotic grippers. Among various gripper technologies, the vacuum suction grippers provide design simplicity, yet versatility at low cost; however, their application is limited to their fixed shape and size. Here, we present an origami-inspired reconfigurable suction gripper to address adaptability with robotic suction grippers. Constructed from rigid and soft components and driven by compact shape memory alloy actuators, the gripper can effectively self-fold into three shape modes to pick large and small flat, narrow cylindrical, triangular and spherical objects. The 10-g few centimeters gripper lifts loads up to 5 N, 50 times its weight. We also present an underactuated prototype, demonstrating the versatility of our design and actuation methods.

A reconfigurable interactive interface for controlling robotic origami in virtual environments

Origami shape transformation is dictated by predefined folding patterns and their folding sequence. The working principle of robotic origami is based on the same principle: we design quasi-two-dimensional tiles and connecting hinges and define and program their folding sequences. Since the tiles are often of uniform shape and size, their final configuration is governed by the kinematic relationship. Mathematicians, computer scientists and even architects have studied a wide range of origami algorithms. However, for multiple shape transformations, the origami design parameters and consequently sequence planning become more challenging. In this work, we present a reconfigurable interactive interface, a physics-based modeling control interface to explore the design space of origami robots. We developed two interactive modes for proof of concept of a bidirectional communication interface between virtual and physical environments. The first interaction mode is origami-inspired, foldable surfaces with distributed sensors that can recreate folding sequences and shape transformations in a virtual environment via hardware-in-loop simulation. Its complementary digital transcription lays the foundation for a robotic origami design tool that provides visual representation of various design formulations as well as an intuitive controller for robotic origami. In the second interaction mode, we construct a physics-based modeling interface for intuitive user manipulation of robotic origami in a virtual environment. Algorithms for graphical representation and command transformation were developed for robotic interaction. Lastly, we tested the efficacy of the algorithms on prototypes to discover the applications and capacities of the reconfigurable interactive interface.

Tribot: A deployable, self-righting and multi-locomotive origami robot

There are several challenges in down-sizing robots for transportation deployment, diversification of locomotion capabilities tuned for various terrains, and rapid and on-demand manufacturing. In this paper we propose an origami-inspired method of addressing these key issues by designing and manufacturing a foldable, deployable, and self-righting version of the origami robot Tribot. Our latest Tribot prototype can jump as high as 215 mm, five times its height, and roll consecutively on any of its edges with an average step size of 55 mm. The 4 g robot self-deploys nine times of its size when released. A compliant roll cage ensures that the robot self-rights onto two legs after jumping or being deployed and also protects the robot from impacts. A description of our prototype and its design, locomotion modes, and fabrication is followed by demonstrations of its key features.

Implementation of a novel complex mechatronics software framework on laser micromachining workstation

As technology brings more complex and sophisticated systems, the importance of the problem of designing and developing a mechatronic system increases as well and it becomes more complicated to obtain a reliable, accurate and sustainable system. Since complex systems are generally composed of many different types of sub-systems, a necessity for a systematic approach towards the development arises. In this paper, the problem of software development for complex mechatronic systems is addressed and a novel software framework is proposed in order to provide common design and development criteria and related software structures. As an implementation of the framework and to present a proof of concept, software for a laser micromachining workstation is developed from scratch using this framework. Experiments are conducted using the workstation and results are provided.

Nanometric positioning of a piezo walker

This work presents functional description of a walking piezoelectric motor and its control in nanometer precision. For this purpose a dynamical model of the actuator is derived based on simple mass spring damper system. Model parameters are estimated from step response plot and the system is expressed with second order transfer function. Additional identification experiments verified the theoretical kinematics of the bimorph legs. These experiments demonstrate approximately linear relation between the legs displacement in x and y directions to the applied voltages. Based on derived system model and identification results a PI controller followed by Hadamard transformation is proposed as a controller scheme. Experimental results for staircase and sinusoidal references reveal precise positioning capabilities of the system with the proposed control scheme down to few nanometers.