DEPUSH HexCrawler: Mechanical and Control System Improvement

The DEPUSH HexCrawler robot has a dated control system and walking mechanism making it unstable and clumsy. DEPUSH asked our team to update the HexCrawler in conjunction with HUST students from Wuhan, China. The team redesigned the robot\u27s chassis and legs to increase mobility and stability, and implemented a powerful control system capable of precisely manipulating the robot\u27s limbs. The resulting product is a 6 Degree-of-Freedom hexapod and accompanying computer interface with applications in a variety of robotics research areas

DEPUSH HexCrawler Improvement Project

DEPUSH Technologies purchased the rights to an older six-legged walking robot design and sought help from WPI and HUST students to improve its functionality to better meet the needs of the secondary education market in mainland China. To accomplish this goal, both the mechanical walking system and control system were improved. The mechanical structure was redesigned for three degree of freedom legs and a more robust chassis, while an entirely new control system was utilized to implement full inverse body and walking kinematics. The result was a cutting-edge hexapod, the HexCrawler 2.0, a versatile platform with potential applications in a variety of robotics-related projects and solid foundation for future research on high-level control

Human Activity Recognition and Control of Wearable Robots

abstract: Wearable robotics has gained huge popularity in recent years due to its wide applications in rehabilitation, military, and industrial fields. The weakness of the skeletal muscles in the aging population and neurological injuries such as stroke and spinal cord injuries seriously limit the abilities of these individuals to perform daily activities. Therefore, there is an increasing attention in the development of wearable robots to assist the elderly and patients with disabilities for motion assistance and rehabilitation. In military and industrial sectors, wearable robots can increase the productivity of workers and soldiers. It is important for the wearable robots to maintain smooth interaction with the user while evolving in complex environments with minimum effort from the user. Therefore, the recognition of the user's activities such as walking or jogging in real time becomes essential to provide appropriate assistance based on the activity. This dissertation proposes two real-time human activity recognition algorithms intelligent fuzzy inference (IFI) algorithm and Amplitude omega ($A \omega$) algorithm to identify the human activities, i.e., stationary and locomotion activities. The IFI algorithm uses knee angle and ground contact forces (GCFs) measurements from four inertial measurement units (IMUs) and a pair of smart shoes. Whereas, the $A \omega$ algorithm is based on thigh angle measurements from a single IMU. This dissertation also attempts to address the problem of online tuning of virtual impedance for an assistive robot based on real-time gait and activity measurement data to personalize the assistance for different users. An automatic impedance tuning (AIT) approach is presented for a knee assistive device (KAD) in which the IFI algorithm is used for real-time activity measurements. This dissertation also proposes an adaptive oscillator method known as amplitude omega adaptive oscillator ($A\omega AO$) method for HeSA (hip exoskeleton for superior augmentation) to provide bilateral hip assistance during human locomotion activities. The $A \omega$ algorithm is integrated into the adaptive oscillator method to make the approach robust for different locomotion activities. Experiments are performed on healthy subjects to validate the efficacy of the human activities recognition algorithms and control strategies proposed in this dissertation. Both the activity recognition algorithms exhibited higher classification accuracy with less update time. The results of AIT demonstrated that the KAD assistive torque was smoother and EMG signal of Vastus Medialis is reduced, compared to constant impedance and finite state machine approaches. The $A\omega AO$ method showed real-time learning of the locomotion activities signals for three healthy subjects while wearing HeSA. To understand the influence of the assistive devices on the inherent dynamic gait stability of the human, stability analysis is performed. For this, the stability metrics derived from dynamical systems theory are used to evaluate unilateral knee assistance applied to the healthy participants.Dissertation/ThesisDoctoral Dissertation Aerospace Engineering 201

Development of an Underground Mine Scout Robot

Despite increased safety and improved technology in the mining industry, fatal disasters still occur. Robots have the potential to be an invaluable resource for search and rescue teams to scout dangerous or difficult situations. Existing underground mine search and rescue robots have demonstrated limited success. Identified through literature, the two primary concerns are unreliable locomotion systems and a lack of underground mine environment consideration. HADES, an underground mine disaster scout, addresses these issues with a unique chassis and novel locomotion. A system level design is carried out, addressing the difficulties of underground mine environments. To operate in an explosive atmosphere, a purge and pressurisation system is applied to a fibre glass chassis, with intrinsic safety incorporated into the sensor design. To prevent dust, dirt and water damaging the electronics, ingress protection is applied through sealing. The chassis is invertible, with a low centre of gravity and a roll-axis pivot. This chassis design, in combination with spoked-wheels allows traversal of the debris and rubble of a disaster site. Electrochemical gas sensors are incorporated, along with RGB-D cameras, two-way audio and various other environment sensors. A communication system combining a tether and mesh network is designed, with wireless nodes to increase wireless range and reliability. Electronic hardware and software control are implemented to produce an operational scout robot. HADES is 0.7 × 0.6 × 0.4 m, with a sealed IP65 chassis. The locomotion system is robust and effective, able to traverse most debris and rubble, as tested on the university grounds and at a clean landfill. Bottoming out is the only problem encountered, but can be avoided by approaching obstacles correctly. The motor drive system is able to drive HADES at walking speed (1.4 m/s) and it provides more torque than traction allows. Six Lithium-Polymer batteries enable 2 hours 28 minutes of continuous operation. At 20 kg and ~$7000, HADES is a portable, inexpensive scout robot for underground mine disasters

Architecture and awareness of self.

Thesis. 1975. M.Arch.--Massachusetts Institute of Technology. Dept. of Architecture.Bibliography: leaves 147-149.M.Arch

Computer aided stress analysis of the femur with prosthetic hip stem utilizing computed tomography

A computer aided design and analysis method, utilizing computed tomography (CT) is developed, which together with a finite element program determines the stress and deformation patterns in the femur with hip prosthesis. The CT scan data file provides the geometry and the material parameters for the generated finite element model. The three-dimensional finite element model of the femur with hip prosthesis is automatically generated from the CT data file by a preprocessing procedure. The preprocessor includes a CT image display, edge detector, nodes generation, prosthesis simulator, mesh generator and model display. The loading conditions applied on the finite element model are determined from existing gait analysis including joint force and muscle force. Formatted input data for ANSYS (Swanson Analysis Systems Inc.) finite element program is generated by the preprocessor. In this research, the influence on the stress pattern of different prosthetic materials and fixation, such as cobalt-chromium alloy or titanium alloy prosthesis, also cemented or porous-coated prosthesis are studied. A comparison of the stress patterns for the three different femora is made and a radiographic follow-up study in two cases is carried out at 14 months and 12 months postoperation for analyzing the bone remodeling process. As a result of the calculated stress patterns in the femur with prosthesis, it is found that the cobalt-chromium alloy prosthesis unloads the calcar cortical bone and the titanium alloy prosthesis decreases the stress within the prosthetic stem except for the proximal side. The highest calculated stress is approximately 12% of the fatigue limit for cobalt-chromium alloy prosthesis, and approximately 4% for the titanium alloy prosthesis. Comparing the porous coating model with the cemented model, the porous coating model leads to decreased bone stresses, reduced stress concentrations in bone surrounding the prosthesis and more uniformly distributed stress to the surrounding bone tissue. For the effect of stiffness and Poisson\u27s ratio of the porous coating layer, lower elastic modulus and Poisson\u27s ratio will reduce the interface stress between cancellous bone and the porous coating layer. The average stress of the fractured femur with prosthesis is approximately twice the amount of the femur with prosthesis in the proximal and distal side of the prosthetic stem. Furthermore the average stress of the male femur with prosthesis is about 4% lower than the female femur with prosthesis. In regards to stress changes in the postoperative femur, the bone remodeling results indicate that bone resorption of the cortex around the proximal prosthesis would increase the stress in the proximal prosthetic stem and femoral surface slightly while decreasing the stress of the midregion. Bone hypertrophy around the distal prosthesis would decrease the stress up to 35% in the distal prosthetic stem and femoral surface

A social interpretation of the castle in Scotland

Space is not something just out there. It is a human construct, to which architecture can give lasting form. Taking this as a premise, this thesis has investigated the castellated architecture of Scotland, not as a military fortress or an expression of architectural genius, but as a structure where people lived and which influenced how they lived. In achieving this aim, certain techniques of spatial analysis have been used, access analysis and planning diagrams, alongside a more experiential approach to the castle. The combination of these techniques has helped in providing an engagement with the material culture, which would not have been possible singularly. This engagement has been made all the richer for the extensive use of documentary sources to provide a context for the multitude of spatial relations which took place in and around the castle. The castles which form the case-studies are Dirleton (East Lothian), Bothwell (Lanarkshire), Tulliallan (Fife), Morton (Dumfriesshire) and Elphinstone (East Lothian). The selection thus encompasses curtain wall castles, hall houses and tower houses. The analysis has brought about a greater understanding of the individual case-studies. However, the conclusion reached about the nature of space within the castle has been widened out by relating the findings to other castles. Most interestingly, the analysis has suggested what one could call the 'privatisation of space' in late sixteenth century Scotland. This change in material culture coincided with dramatic religious, political and social changes

German Ageing Survey (DEAS): Instruments of the Fifth Wave 2014

Capi-Template for the face-to-face interview; Drop-off questionnaire; Short questionnaire for non-respondents; Occupational status card; Cards with personal codes; Answer options (excerpt); Digit-symbol test; Pulmonary function test