scholarly journals Gait Regulation of a Bionic Quadruped Robot with Antiparallelogram Leg Based on CPG Oscillator

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jiupeng Chen ◽  
Hongjun San ◽  
Xing Wu
Keyword(s):  
Control Algorithm ◽  
Weight Bearing ◽  
Quadruped Robot ◽  
Smooth Transition ◽  
Control Mode ◽  
Trot Gait ◽  
Development Cycle ◽  
Strength And Stiffness ◽  
The Right ◽  
Hopf Oscillator

In order to shorten the research and development cycle of quadruped robot, it is significant to solve the problem of single leg weight-bearing and obtain a smooth gait switching. Firstly, a leg structure with an antiparallelogram is proposed, which greatly enhances the strength and stiffness of the leg in this paper. Secondly, the Simulink-ADAMS cosimulation platform is built and the improved Hopf oscillator is used in the control of robot. This control mode based on CPG realizes the walk and trot gait of quadruped robot. Thirdly, in order to solve the problems of breakpoints, phase-locked, and stopping of gait curve in the process of gait switching by directly replacing the gait matrix, the functional relationship between the right hind leg and duty cycle is introduced to realize the smooth transition of gait curve. The simulation results show that the proposed algorithm can achieve a smooth gait transformation within 4–6 second, which preliminarily proves the feasibility of the algorithm. Finally, the experimental platform is built and the control algorithm is written into the controller to realize the specific gait of the robot, which proves the effectiveness of the proposed method.

scholarly journals Motion coordination control of planar 5R parallel quadruped robot based on SCPL-CPG

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110709
Author(s):  
Mingfang Chen ◽  
Kangkang Hu ◽  
Yongxia Zhang ◽  
Fengping Qi
Keyword(s):  
Control System ◽  
Control Strategy ◽  
Robot Control ◽  
Quadruped Robot ◽  
Smooth Transition ◽  
Analysis Method ◽  
Motion Coordination ◽  
Connection Weight ◽  
Unit Model ◽  
Hopf Oscillator

The parallel leg of the quadruped robot has good structural stiffness, accurate movement, and strong bearing capacity, but it is complicated to control. To solve this problem, a series connection of parallel legs (SCPL) was proposed, as well as a control strategy combined with the central pattern generator (CPG). With the planar 5R parallel leg as the research object, the SCPL analysis method was used to analyze the leg structure. The topology of CPG network was built with the Hopf oscillator as the unit model, and the CPG was the core to model the robot control system. By continuously adjusting the parameters in the CPG control system and changing the connection weight, and the smooth transition between gaits was realized. The simulation results show that the SCPL analysis method can be effectively used in the analysis of parallel legs, and the control system can realize the smooth transition between gaits, which verifies the feasibility and effectiveness of the proposed control strategy.

scholarly journals Unprecedented tibial bone lengthening of 33.5 cm by distraction osteogenesis for the reconstruction of a subtotal tibial bone defect. A case report and literature review

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Abdulnassir Ali ◽  
Ying Ren ◽  
Chun-Hao Zhou ◽  
Jia Fang ◽  
Cheng-He Qin
Keyword(s):  
Bone Defect ◽  
Distraction Osteogenesis ◽  
Chronic Osteomyelitis ◽  
Weight Bearing ◽  
Lower Leg ◽  
Bone Lengthening ◽  
Case Presentation ◽  
Tibial Length ◽  
Tibial Bone ◽  
The Right

Abstract Background We present a case of an immense unprecedented tibial bone lengthening of 33.5 cm. The management of chronic osteomyelitis of the right tibia with subtotal tibial bone defect, talus defect and equinus ankle deformity. We demonstrate limb reconstruction by distraction osteogenesis and correction of ankle deformity with the Ilizarov technique. Limb salvage was preferred as an alternative to amputation to restore basic limb function. Case presentation A 16-year-old male patient fell and injured his right lower leg. He attempted to treat the symptoms with traditional home remedies. During 15 months of self-treating, he developed osteomyelitis of the right tibia and had lost function in his foot. Radiology revealed immense bone defect of the right tibia, including talus bone defect and equinus deformity of the calcaneus. The patient’s right tibia was non weight-bearing, had drainage sinus just below his knee and a large scar anteriorly along the entire length of the tibia. Conclusion Upon completion of treatment, the patient was able to avoid amputation of his leg with partially restored function for weight-bearing. He carried himself without assistance after 3 years of lost function in his right leg. Tibial bone distraction osteogenesis of 33.5 cm was done after 90% of the tibial length was defected. To the best of our best knowledge, this case is one of a kind to achieve distraction of tibial bone to such length.

Structural design and gait research of a new bionic quadruped robot

2021 ◽  
pp. 095440542199566
Author(s):  
Jiu-Peng Chen ◽  
Hong-Jun San ◽  
Xing Wu ◽  
Bin-Zhou Xiong
Keyword(s):  
Stability Margin ◽  
Static Stability ◽  
Quadruped Robot ◽  
Superior Performance ◽  
Linkage Mechanism ◽  
Wide Range ◽  
Planning Algorithm ◽  
Planning Experiment ◽  
Strength And Stiffness ◽  
Foot Trajectory

Quadruped bionic robot has a strong adaptability to the environment, compared with wheeled and tracked robots, it has superior motion performance, and has a wide range of application prospects in rescue and disaster relief, ground mine clearance, mountain transportation, so it has become a research hotspot all over the world. Leg structure is an important embodiment of the superior performance of quadruped robot, and it is also the key and difficult point of design. This article proposes a novel quadruped robot with waist structure, which can complete a variety of gait forms. Based on the theory of linkage mechanism, a novel leg structure is designed with anti-parallelogram mechanism, which improves the strength and stiffness of the robot. Using D-H description method, the kinematics analysis of this quadruped robot single leg is carried out. On this basis, in order to ensure the foot contact with the ground and achieve zero impact, polynomial programming is used to plan the foot trajectory of swing phase and support phase. Based on the static stability margin, the optimal static gait of the quadruped robot is planned. A co-simulation study has been carried out to investigate further the validity and effectiveness of the quadruped robot on gait. The simulation results clearly show the robot can walk steadily and its input and output meet the expected requirements. The solid prototype platform is built, and the trajectory planning experiment of single leg is carried out, and the foot trajectory of single leg is obtained by using laser tracker. The gait planning algorithm is applied to the whole robot, and the results show that the robot can walk according to the scheduled gait, which proves the effectiveness of the proposed algorithm.

Effect of unweighting on skeletal muscle use during exercise

1995 ◽  
Vol 79 (1) ◽  
pp. 168-175 ◽  
Author(s):  
L. L. Ploutz-Snyder ◽  
P. A. Tesch ◽  
D. J. Crittenden ◽  
G. A. Dudley
Keyword(s):  
Lower Limb ◽  
Weight Bearing ◽  
Muscle Group ◽  
Mr Images ◽  
Cross Sectional ◽  
Quadriceps Femoris Muscle ◽  
Before And After ◽  
Exercise Induced ◽  
The Right ◽  
Femoris Muscle

Exercise-induced spin-spin relaxation time (T2) shifts in magnetic resonance (MR) images were used to test the hypothesis that more muscle would be used to perform a given submaximal task after 5 wk of unweighting. Before and after unilateral lower limb suspension (ULLS), 7 subjects performed 5 sets of 10 unilateral concentric actions with the quadriceps femoris muscle group (QF) at each of 4 loads: 25, 40, 55, and 70% of maximum. T2-weighted MR images of the thigh were collected at rest and after each relative load. ULLS elicited a 20% decrease in strength of the left unweighted QF and a 14% decrease in average cross-sectional area (CSA) with no changes in the right weight-bearing QF. Average CSA of the left or right QF showing exercise-induced T2 shift increased as a function of exercise intensity both before and after ULLS. On average, 12 +/- 1, 15 +/- 2, 18 +/- 2, and 22 +/- 1 cm2 of either QF showed elevated T2 for the 25, 40, 55, and 70% loads, respectively, before ULLS. Average CSA of the left but not the right QF, showing elevated T2 after ULLS, was increased to 16 +/- 2, 23 +/- 3, 31 +/- 7, and 39 +/- 5 cm2, respectively. The results indicated that unweighting increased exercise-induced T2 shift in MR images, presumably due to greater muscle mass involvement in exercise after than before unweighting, suggesting a change in motor control.

scholarly journals Changes in Midbrain Pain Receptor Expression, Gait and Behavioral Sensitivity in a Rat Model of Radiculopathy

2012 ◽  
Vol 6 (1) ◽  
pp. 383-391 ◽  
Author(s):  
Priscilla Y Hwang ◽  
Kyle D Allen ◽  
Mohammed F Shamji ◽  
Liufang Jing ◽  
Brian A Mata ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Radicular Pain ◽  
Receptor Expression ◽  
Motor Deficits ◽  
Intervertebral Disc Herniation ◽  
Metabotropic Glutamate ◽  
Behavioral Sensitivity ◽  
Inflammatory Processes ◽  
Pain Receptors ◽  
The Right

Intervertebral disc herniation may contribute to inflammatory processes that associate with radicular pain and motor deficits. Molecular changes at the affected dorsal root ganglion (DRG), spinal cord, and even midbrain, have been documented in rat models of radiculopathy or nerve injury. The objective of this study was to evaluate gait and the expression of key pain receptors in the midbrain in a rodent model of radiculopathy. Radiculopathy was induced by harvesting tail nucleus pulposus (NP) and placing upon the right L5 DRG in rats (NP-treated, n=12). Tail NP was discarded in sham-operated animals (n=12). Mechanical allodynia, weight-bearing, and gait were evaluated in all animals over time. At 1 and 4 weeks after surgery, astrocyte and microglial activation was tested in DRG sections. Midbrain sections were similarly evaluated for immunoreactivity to serotonin (5HT2B), mu-opioid (µ-OR), and metabotropic glutamate (mGluR4 and 5) receptor antibodies. NP-treated animals placed less weight on the affected limb 1 week after surgery and experienced mechanical hypersensitivity over the duration of the study. Astroctye activation was observed at DRGs only at 4 weeks after surgery. Findings for pain receptors in the midbrain of NP-treated rats included an increased expression of 5HT2B at 1, but not 4 weeks; increased expression of µ-OR and mGluR5 at 1 and 4 weeks (periaqueductal gray region only); and no changes in expression of mGluR4 at any point in this study. These observations provide support for the hypothesis that the midbrain responds to DRG injury with a transient change in receptors regulating pain responses.

The Study of Numerical Control Algorithm and Hardware

2012 ◽  
Vol 488-489 ◽  
pp. 1697-1701
Author(s):  
Rui Wu ◽  
Yuan Kui Xu
Keyword(s):  
Information Processing ◽  
Control System ◽  
Machine Tools ◽  
Control Algorithm ◽  
Numerical Control ◽  
Numerical Control System ◽  
Manufacturing Control ◽  
Hardware System ◽  
Continuous Progress ◽  
The Right

With the continuous progress of science and technology, manufacturing has been a huge space for development. Nowadays numerical control system is widely used in manufacturing. Numerical control system is actually manufacturing control system. By actual information required, with decoded by computer, after information processing It will the process control operations of machine tools to process out the right components. With more complexity of manufacturing, we have higher requirements to pretreatment data of numerical control system. This paper will focus on numerical control algorithm and hardware system to study.

Algorithmic support of low-altitude aircraft flight based on the hazard analysis of the flight situation

2021 ◽  
Author(s):  
V.A. Malyshev ◽  
A.S. Leontyev ◽  
S.P. Poluektov ◽  
Е.М. Volotov
Keyword(s):  
Adaptive Control ◽  
Flight Control ◽  
Control Algorithm ◽  
Hazard Analysis ◽  
Critical Value ◽  
Control Mode ◽  
Manual Control ◽  
Flight Safety ◽  
Low Altitude ◽  
Adaptive Control Algorithm

Low-altitude flight of an aircraft is an effective, but at the same time, a very complex tactical technique, during which the crew does not always have the opportunity to timely recognize the occurrence of an abnormal case, determine the way out of it and counteract an aviation accident development. Despite many advantages of the automatic mode of low-altitude flight performing, its practical implementation is associated with a number of features and disadvantages, which determined the preference for the manual mode of low-altitude flight control. These are the presence of telltale factors, limited ability of performing flights at night and in difficult weather conditions, insufficient reliability etc. The considered features determined the relevance of the of low-altitude flight safety ensuring problem in relation to the manual control mode. As a result of an experimental study of the low-altitude flight performing process in a manual control mode, it was found that when performing manually-controlled low-altitude flight, a hazard assessment of the flight situation becomes pivotal. However the crew being under such conditions is not always able to correctly assess the flight situation hazard due to a combination of objective reasons. The current state of the adaptive and on-board flight safety systems theory makes it possible to increase the safety of the manuallycontrolled low-altitude flight by using adaptive control algorithms based on the flight situation hazard assessment. To solve this problem an adaptive control algorithm is proposed that ensures the formation of a security corridor in the longitudinal control channel, where the upper limit is determined by the critical value of the aircraft detection hazard, and the lower limit is determined by the critical value of the error in maintaining a given flight altitude. For a continuous assessment of the flight situation hazard and the timely formation of control signals the complex information about the current true flight altitude and the foreground is needed. Taking into account the peculiarities of low-altitude flight a digital terrain map containing data on natural and artificial obstacles along the flight route is a more rational source of information, that will make it possible to predict the development of the flight situation hazard. The above reasoning makes it possible to form an aircraft low-altitude flight adaptive control algorithm. A distinctive feature of the proposed algorithm is the implementation of a combined control variety where the pilot is provided with ample manual control opportunities within the security corridor, and the automatic flight control system is assigned the role of a safety subsystem that ensures control and timely return of the flight situation to normal flight conditions. The presented algorithm will allow to increase the crew logical-analytical activity information support during continuous analysis of the existing flight situation due to the formation of protective control actions based on the current flight situation hazard analysis.

Muscle glucose uptake in the rat after suspension with single hindlimb weight bearing

1993 ◽  
Vol 74 (5) ◽  
pp. 2072-2078 ◽  
Author(s):  
C. S. Stump ◽  
C. R. Woodman ◽  
R. F. Fregosi ◽  
C. M. Tipton
Keyword(s):  
Glucose Uptake ◽  
Body Mass ◽  
Extracellular Space ◽  
Simulated Microgravity ◽  
Weight Bearing ◽  
Cage Control ◽  
Hindlimb Muscles ◽  
Loss Of Mass ◽  
The Right ◽  
Gastrocnemius Muscles

This study was designed to examine the effect of non-weight-bearing conditions and the systemic influences of simulated microgravity on rat hindlimb muscles. For this purpose, rats were suspended (SUS) in a head-down position (45 degrees) with the left hindlimb non-weight bearing (NWB) and the right hindlimb bearing 20% of presuspension body mass (WB). Weight bearing by the SUS-WB limb was accomplished by using a platform connected to a rod in sleeve, cable, and pulley apparatus to which weight could be added. Rats (250–325 g) were assigned to SUS or cage control (CC) conditions for 14 days. The angle between the foot and leg for SUS-WB and CC remained similar (20–30 degrees) throughout the experiment while the SUS-NWB hindlimbs extended to approximately 140 degrees by day 12. On day 14, the soleus, plantaris, and gastrocnemius muscles from the SUS-NWB limbs exhibited significantly lower (P < or = 0.05) masses than presuspension mass values (29, 11, and 21%, respectively). Weight bearing by the SUS-WB limbs prevented the loss of mass by these muscles. In separate groups of SUS and CC rats, 2-deoxyglucose uptake during hindlimb perfusion was significantly higher in both SUS-NWB and SUS-WB hindlimbs at 24,000 microU/ml of insulin compared with CC for all the muscles examined (21–80%). In addition, extracellular space (ml/g) was significantly greater in the soleus muscles from both the SUS-NWB and SUS-WB hindlimbs (64%) compared with CC muscles.

scholarly journals A Suspicious Atypical Fracture of 5th Metatarsal Bone: A Case Report

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0033
Author(s):  
Byeong-Seop Park ◽  
Seungbum Koo ◽  
Won-keun Park ◽  
Ki-bum Kwon ◽  
Kyoung Min Lee
Keyword(s):  
Callus Formation ◽  
Weight Bearing ◽  
Femoral Fractures ◽  
Metatarsal Bone ◽  
Atypical Fracture ◽  
Atypical Fractures ◽  
Strenuous Activity ◽  
History Of ◽  
Surgical Fixation ◽  
The Right

Category: Trauma Introduction/Purpose: Long-term usage of bisphosphonate can severely suppress bone turnover and alter bone mechanical properties, thereby resulting in atypical fractures that mainly occur at the femur.We present a rare case of suspicious atypical fracture of the metatarsal bone. Methods: A 63-year-old woman presented to our clinic with a primary complain of a one-week history of pain in her right foot. The patient had no history of trauma to the right foot and denied any strenuous activity. She experienced lateral foot pain while walking within her home. She was on alendronate therapy for osteoporosis for a decade. X ray and CT examination revealed a fifth metatarsal fracture whose features were compatible with those of atypical femoral fractures (Figure 1). Results: The patient was advised to discontinue alendronate and underwent percutaneous surgical fixation of the fracture via a proximal approach using a 4.0-mm half-threaded cannulated screw. Postoperatively, a short leg cast was created and the patients performed non-weight bearing ambulation until the cast was removed at the sixth postoperative week. Radiography in the sixth postoperative week revealed callus formation. Conclusion: Our findings suggest that physicians must keep in mind that atypical fractures could possibly occur at bones other than the femur.

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