Tension Distribution Research Articles

Direct method for tension feasible region calculation in multi-redundant cable-driven parallel robots using computational geometry

With a low moving inertia, high payload-to-weight ratio, and large workspace, cable-driven parallel robots (CDPRs) are relevant in many applications, especially redundant CDPRs. As there exist an infinite number of tension distributions, this paper presents a novel computational geometry-based method to calculate a tension feasible region (TFR)—a preimage of tension distribution—for multi-redundant CDPRs. The proposed TFR algorithm overcomes some of the limitations of conventional iterative and vertices search methods. The TFR is first interpreted as a convex intersection of multiple boundary-parallel spaces, where its dimension is equal to redundancy r. To obtain the centroid of TFR, the vertices coordinates and order for r = 2 and 3 only need to be determined on surface. Static simulations with 6 degrees-of-freedom using 8-cable and 9-cable CDPRs are employed to demonstrate the algorithmic accuracy. Additionally, to illustrate that the optimal tension distribution has continuity, motion trajectories for the same CDPRs are calculated. Furthermore, the proposed algorithm minimizes computational time when compared to the performance of existing algorithms. Thus, the proposed method could rapidly establish the optimal tension distribution.

Synergy between different sulfobetaine-type zwitterionic Gemini surfactants: Surface tension and rheological properties

Salt-resistant, heat-resistant, and viscoelastic properties are critical for fluids used in oil fields, and one approach of producing these high- performance fluids is to use a mixture of different surfactants. Herein, we present a detailed study on the development of a mixture fluid consisting of two different sulfobetaine-type zwitterionic Gemini surfactants: EDABS and EDAES. Different molar ratio mixtures were evaluated in terms of the surface tension, salt-resistance and particle size distribution of the mixture. The BES-3 fluid, consisting of EDABS and EDAES with the molar ratio of 1 to 1, has the best salt-resistance, due to their strong interactions. The BES-3 fluid exhibited superior viscoelasticity, shear-tolerance, and temperature-tolerance as a result of the strong network structures formed by entangled wormlike micelles of the interacted surfactants in solution. Therefore, these exciting results show strong potential for the BES-3 fluid to be employed as rheological modifier in fracturing fluid and oil-displacing agents.

Cable Tension Analysis Oriented the Enhanced Stiffness of a 3-DOF Joint Module of a Modular Cable-Driven Human-Like Robotic Arm

Inspired by the structure of human arms, a modular cable-driven human-like robotic arm (CHRA) is developed for safe human–robot interaction. Due to the unilateral driving properties of the cables, the CHRA is redundantly actuated and its stiffness can be adjusted by regulating the cable tensions. Since the trajectory of the 3-DOF joint module (3DJM) of the CHRA is a curve on Lie group SO(3), an enhanced stiffness model of the 3DJM is established by the covariant derivative of the load to the displacement on SO(3). In this paper, we focus on analyzing the how cable tension distribution problem oriented the enhanced stiffness of the 3DJM of the CHRA for stiffness adjustment. Due to the complexity of the enhanced stiffness model, it is difficult to solve the cable tensions from the desired stiffness analytically. The problem of stiffness-oriented cable tension distribution (SCTD) is formulated as a nonlinear optimization model. The optimization model is simplified using the symmetry of the enhanced stiffness model, the rank of the Jacobian matrix and the equilibrium equation of the 3DJM. Since the objective function is too complicated to compute the gradient, a method based on the genetic algorithm is proposed for solving this optimization problem, which only utilizes the objective function values. A comprehensive simulation is carried out to validate the effectiveness of the proposed method.

Reaction Wood Anatomical Traits and Hormonal Profiles in Poplar Bent Stem and Root.

Reaction wood (RW) formation is an innate physiological response of woody plants to counteract mechanical constraints in nature, reinforce structure and redirect growth toward the vertical direction. Differences and/or similarities between stem and root response to mechanical constraints remain almost unknown especially in relation to phytohormones distribution and RW characteristics. Thus, Populus nigra stem and root subjected to static non-destructive mid-term bending treatment were analyzed. The distribution of tension and compression forces was firstly modeled along the main bent stem and root axis; then, anatomical features, chemical composition, and a complete auxin and cytokinin metabolite profiles of the stretched convex and compressed concave side of three different bent stem and root sectors were analyzed. The results showed that in bent stems RW was produced on the upper stretched convex side whereas in bent roots it was produced on the lower compressed concave side. Anatomical features and chemical analysis showed that bent stem RW was characterized by a low number of vessel, poor lignification, and high carbohydrate, and thus gelatinous layer in fiber cell wall. Conversely, in bent root, RW was characterized by high vessel number and area, without any significant variation in carbohydrate and lignin content. An antagonistic interaction of auxins and different cytokinin forms/conjugates seems to regulate critical aspects of RW formation/development in stem and root to facilitate upward/downward organ bending. The observed differences between the response stem and root to bending highlight how hormonal signaling is highly organ-dependent.

Influence of wear on the distribution of pressure and the state of tension at wheel-rail interface

Since no effective experimental approaches have been proposed to assess state of stress and distribution of pressures at the wheel and rail contact interface to date, numerical calculation methods are known as an alternative to approximate modelling of wheel-rail interaction. In this paper, a numerical procedure is proposed based on the finite element method of the complex tensions state on wheel-rail contact. This study includes the distribution of pressures and tensions on wheel-rail contact system with new and worn profiles, using a finite element modeling (FEM). Using a model of isotropic elastic-plastic material was obtained a FE model that can obtain the distribution of pressures and tensions at the wheel-rail interface for the real surfaces that are in contact, this model is necessary for any tribological study that requires data on the state of stress and pressure only by introducing input data: geometric characteristics, Young’s Modulus, Poisson’s Ratio, Tangent Modulus, Yield Strength, load on the wheel, lateral shift of wheelset.

A Modified Surgical Method Combined with Blepharoplasty Design for Treatment of Xanthelasma Palpebrarum.

Purpose Xanthelasma palpebrarum manifests as a yellowish placoid on the medial aspect of the upper eyelids, often in middle and old age. Aggravated lateral hooding of the eyelid might cause a deformity with conventional surgery, which appears to be more deficient on the medial side with excess hooding of the lateral skin. The authors suggest a novel surgical technique to solve this problem and reconstruct the defect appropriately. Methods From July 2017 to December 2018, our method of combining excision with blepharoplasty was performed on 8 patients, consisting of 15 lesions on the upper eyelid and 6 lesions on the lower lid. Lesion removal incorporating blepharoplasty incision was done. After resection, the orbicularis oculi musculocutaneous flap was widely elevated extending through the whole upper eyelid with the lateral flap first along with fat maneuver. The flap was advanced into the defect, with even distribution of tension, after lower flap fixation to the required height of the eyelid fold. Taping was done with a hydrocolloid bandage and kept for 2 weeks. Results The wounds were healed primarily, and no cases of recurrence, lagophthalmos, hypertrophic scar, pigmentation, or remarkable deformity were noted. All patients were satisfied, and the functional outcomes were excellent. Two patients had trivial complications specific to our method, that of triple fold and neo-Mongolian fold, which were simply revised later. Conclusions This modality overcame the drawbacks of eyelid deformity observed in previous surgical methods, giving excellent results without any critical complications.

Coordinated Dynamic Control in the Task Space for Redundantly Actuated Cable-Driven Parallel Robots

Although cable-driven parallel robots (CDPRs) act as parallel mechanisms that are driven by multiple cables coordinately, the coordination motion analysis is often omitted. Therefore, the coordination effect in the task space (TS) of redundantly actuated CDPRs is addressed in this article, and a scheme of the coordinated dynamic control in the TS (CDCT) is proposed to guarantee high-precision control. Additionally, to handle the inevitable external disturbances, the robust analysis is also synthesized in the CDCT scheme, and the stability of the whole control system is proved. Moreover, due to the existing actuation redundancy, the cable tension distribution method is presented to ensure that all cables are always kept in tension. Trajectory tracking experiments are carried out on the redundantly actuated CDPR, and the augmented PD (APD) scheme without coordination and robust effect and the CDCT scheme without robust effect (CDCT-wR) are used for comparisons. The results show that, there is a significant effect of the coordinated control with a better coordination performance by using the CDCT scheme, and the final tracking accuracy has an evident improvement. Besides, the satisfactory robustness of the CDCT scheme in resisting external disturbances is also verified via supplementary experiments.

Strategies for Mesh Fixation in Abdominal Wall Reconstruction: Concepts and Techniques.

Ventral hernias have numerous causes, ranging from sequelae of surgical procedures to congenital deformities. Patients suffering from these hernias experience a reduced quality of life through pain, associated complications, and physical disfigurement. Therefore, it is important to provide these patients with a steadfast repair that restores functionality and native anatomy. To do this, techniques and materials for abdominal wall reconstruction have advanced throughout the decades, leading to durable surgical repairs. At the cornerstone of this lies the use of mesh. When providing abdominal wall reconstruction, a surgeon must make many decisions with regard to mesh use. Along with the type of mesh and plane of placement of mesh, a surgeon must decide on the method of mesh fixation. Fixation of mesh provides an equal distribution of tension and a more robust tissue-mesh interface, which promotes integration. There exist numerous modalities for mesh fixation, each with its own benefits and drawbacks. This Special Topic article aims to compare and contrast methods of mesh fixation in terms of strength of fixation, clinical outcomes, and cost-effectiveness. Methods included in this review are suture, tack, fibrin glue, mesh strip, and self-adhering modes of fixation.

Comparative Analisys of Cataract Phakoemulsification, Complicated with the Zonular Weakness

Purpose: To assess the iridocrystalline complex status in patients with cataract, complicated by zonular weakness, before and after surgical treatment. Patients and Methods. The study enrolled 28 patients (29 eyes) with cataract, complicated by zonular weakness (8 women, 20 men, 74.13 ± 8.48 years old). All patients undergone phacoemulsification with IOL implantation and a capsular tension ring (CTR) if it was necessary. In each case optical biometry, ultrasound biomicroscopy and applanation tonometry were provided. After 1, 3 and 6 months postoperatively refractometry, visual acuity measurement, optical biometry, ultrasound biomicroscopy and OCT of the anterior segment were carried out. Results . Patients were divided into 2 groups. In I group (17 eyes) standard phacoemulsification was provided. In II group (11 eyes) it was necessary to implant CTR. 1 patient was excluded due to the extracapsular cataract extraction. Preoperatively angle of the crystalline lens tilt (3.62 ± 0.34° and 1.78 ± 0.27°, p = 0,00) and IOP were higher in group II. 6 months postoperatively UCVA was significantly higher in group II (0.59 ± 0.09 and 0.39 ± 0.21, p = 0.09), upright angle of IOL tilt (0.28 ± 0.35° and 1.40 ± 1.46°, p = 0.10), total zonnular length (14.28 ± 1.00 and 18.93 ± 0.86 mm, p = 0.00) and the value of IOL decentration (0.80 ± 0.17 and 0.20 ± 0.22 mm, p = 0.04) were significantly less in group II. Conclusion . The angle of crystalline lens tilt according to ultrasound biomicroscopy could be considered as an important diagnostic criterion for the CTR implantation necessity during phacoemulsification. CTR implantation provided decrease of IOL tilt and decentration due to a more regular distribution of zonular tension that increases the UCVA postoperatively in complicated cases. OCT of the anterior segment of the eye and ultrasound biomicroscopy application after phacoemulsification gives a great capacity in IOL-capsular complex visualization and measurement.

Synthetic capsule breakup in simple shear flow

Synthetic capsules in which a thin membrane encloses some biological or chemical ingredients are used in diverse industrial and biomedical applications. In extreme flow environments, the hydrodynamic loading acting on the membrane of the capsule may cause large deformation and structural failure. Although previous experimental studies have focused on the rheological behavior of capsules immersed in different types of flow, the mechanical characteristics of capsules under high shear rate and their breakup mechanism remain unclear. To investigate the breakup process in a simple shear flow, capsules based on human serum albumin are fabricated and used in experiments with a Couette flow rheoscope. The deformation of a tank-treading capsule is examined with the tension distribution on the membrane estimated by a simple analytical model, and the effects of membrane pre-stress on tension distribution and deformation are analyzed using non-inflated and inflated capsules. A non-inflated capsule without pre-stress continues to elongate with increasing shear rate until breakup, while an inflated capsule with pre-stress exhibits a plateau in the deformation under a high shear rate. Furthermore, based on the measurement of the time scale of breakup, we suggest that the breakup of a capsule may occur as a result of membrane fatigue. Given sufficiently high shear rate, the rupture of a membrane segment is induced by large-amplitude cyclic stress, which leads to the tear-up of the capsule along its meridional plane and finally the formation of two daughter lumps.

Study of the stressed state in the layers of the composite material of the construction element

Numerical analysis was used to estimate influence of orientation of composite material layers on strain changes in a constructive element. A finite element method was used to conduct a strain-stress state analysis. A cylindric shell with a radius of 300 mm, a height of 600 mm and a wall thickness of 1,56 mm was examined. The shell consisted of eight differently oriented carbon fiber layers, that were impregnated with epoxy resin. Plate Laminate type elements were used to imitate composite layers orientation and to create a model of cylindric shell walls. Lower base of the cylinder had rigid fasteners and the upper base was under external loading. During strain-stress state analysis of composite layers were examined following loading types: axial tension, bend, torsion, internal pressure. Numerical analysis revealed that tension distribution in layers of composites depends on layer orientation and the cylindric shell loading type. Moreover, this paper defines estimated fatigue life of the shell under pulsatory load. It was determined that characteristics of fatigue strength of the constructive element depend on loading type.

Eco-Friendly Cinnamaldehyde Based Emulsion for Phytopathogenic Bacterial Growth Inhibitor

The formulation plays an essential role in achieving the successful delivery and biological activity of any plant protection products. This study aimed to develop a cinnamaldehyde water-based formulation (oil-in-water emulsion) via a high-shear stirring emulsification method. Cinnamaldehyde emulsion was successfully prepared and characterized using different physicochemical parameters (emulsion stability, persistent foaming, accelerated storage at 54°C for 2 weeks, and stability at 0°Cfor one week, as well as pH, surface tension, flash point, viscosity, and particle size distribution). Also, the antibacterial activity was verified in vitro against some important phytopathogenic bacteria; Erwinia amylovora, Pectobacterium aroidearum, Pseudomonas aeruginosa, and Ralstonia solanacearum using well diffusion method. In addition, the minimum inhibition concentration (MIC) was determined by the twofold dilution method. The results revealed that the prepared formulation showed good storage stability, exhibited non-Newtonian shear-thinning behavior and promising antibacterial activity. The inhibition zones against the tested phytopathogenic bacteria were ranged from 10.3 mm to 52.0 mm. MICs of the prepared formulation were 15.63, 31.25, 62.5, and 15.63 μl/ml against Erwinia amylovora, Pectobacterium aroidearum, Pseudomonas aeruginosa and Ralstonia solanacearum, respectively. Our results provide an environmentally friendly formulation with promising activity to control the agricultural crop disease.

Onset of Mechanochromic Response in the High Strain Rate Uniaxial Compression of Spiropyran Embedded Silicone Elastomers.

The molecular processes that accompany dynamic mechanical response to large deformations at high strain rate (≈1000 s-1 or higher) underlie the early stages of damage in materials, but understanding of material response in this regime is typically limited to macroscopic constitutive equations. Here, spiropyran mechanophores are embedded in very short, stress-bearing strands in silicone elastomers, and their mechanochromic response to uniaxial compression is explored in a Split Hopkinson Pressure (or Kolsky) Bar. At strain rates of 1000 s-1 , the onset of mechanochromism occurs at lower strains, but higher stresses, than in the same materials under quasi-static loading. Similar to quasi-static loading, however, a negligible effect of mechanophore structure on the critical strain for colorimetric onset is observed. The results suggest that nonequilibrium, inhomogeneous local tension distributions in the elastomers lead to greater stress in individual strands than at the same strains under equilibrium loading, but that within the regions of force concentration, mechanochromic onset is determined primarily by a limiting local strain threshold.

Effect of rockfill berm on the stability of large geotextile mat dikes on soft clay

This paper investigates the effect of rockfill berms on the stability of large geotextile mat dikes filled with sand built upon soft clay. Finite element analyses were conducted aiming to provide insight into the design of large geotextile mat dikes by using rockfill berms reinforcement. The FE results were validated against previously published data, with good agreement obtained. A parametrical study was then carried out to explore the failure mechanism, limiting stack height and geotextile tension distribution of the dikes. Based on the FE results, two failure mechanisms, i.e. the so-called global and local failure mechanisms, were observed. A formula was proposed to predict the critical width of the base of the dike to differentiate the two mechanisms. It is found that rockfill berm can increase the limiting stack height and safety factor of the dike, and the shape of rockfill berms has a significant influence on the stability of large geotextile mat dikes. Finally, a general design method was proposed to evaluate the required dike height and factor of safety for the design of the large basal-reinforced geotextile mat dikes, which can provide a guidance for practical application.

Assessment of Postural Balance in Women Treated for Breast Cancer.

Background and objectives: Surgery is the primary and most effective treatment of breast cancer. Unilateral mastectomy disrupts the distribution of muscle tension between the right and the left sides of the body. The aim of the study was to evaluate postural balance in patients treated for breast cancer by mastectomy. Materials and methods: A controlled clinical study was conducted on 90 patients who have undergone surgical treatment for breast cancer (mastectomy) 5–6 years prior (Breast Group—BG). The control group (CG) consisted of 74 healthy female volunteers. Analysis of balance was performed using the Alfa stabilography platform. A static test (Romberg’s test) with open and closed eyes was used to assess balance. The following balance parameters were analyzed: path length, statokinesigram area, parameters of deflection and velocity of the foot pressure center. Results: The study demonstrated that patients from BG (5–6 years after surgery) obtained worse results in both tests with open (maximum back deviation, maximum forward deviation, average Y deviation, average Y velocity, path length and path surface area) (p < 0.05) as well as with closed eyes (maximum backward deviation, maximum forward deviation, mean Y deviation and path length) (p < 0.05). Conclusions: Our study demonstrated that women 5–6 years after surgery for breast cancer have impaired balance compared to healthy women, despite physiotherapy.

Electrical Propagation of Vasodilatory Signals in Capillary Networks.

We have developed a computational model to study electrical propagation of vasodilatory signals and arteriolar regulation of blood flow depending on the oxygen tension and agonist distribution in the capillary network. The involving key parameters of endothelial cell-to-cell electrical conductivity and plasma membrane area per unit volume were calibrated with the experimental data on an isolated endothelial tube of mouse skeletal feeding arteries. We have estimated the oxygen saturation parameters in terms of erythrocyte ATP release from the data of a left anterior descending coronary blood perfusion of dog. Regarding the acetylcholine-induced upstream conduction, our model shows that spatially uniform superfusion of acetylcholine attenuates the electrical signal propagation, and blocking calcium-activated potassium channels suppresses that attenuation. On the other hand, a local infusion of acetylcholine induces enhanced electrical propagation that corresponds to physiological relevance. Integrating the electrophysiology of endothelial tube and the electrophysiology/mechanics of a lumped arteriole, we show mechanistically that endothelial purinergic oxygen sensing of ATP released from erythrocytes and local infusion of acetylcholine are individually effective to induce vasodilatory signals to regulate blood flow in arterioles. We have recapitulated the upstream vasomotion in arterioles from the elevated oxygen tension in the downstream capillary domain. This study is a foundation for characterizing effective pharmaceutical strategies for ascending vasodilation and oxygenation.

Evolving concepts in ventral hernia repair and physical therapy: prehabilitation, rehabilitation, and analogies to tendon reconstruction.

The abdominal wall and musculoskeletal tendons share many anatomic, physiologic, and functional characteristics. This review aims to highlight these similar characteristics and to present a rationale why the treatment principles of successful musculoskeletal tendon reconstruction, including principles of surgical technique and physical therapy, can be used in the treatment of complex abdominal wall reconstruction or ventral hernia repair. The MEDLINE/PubMed database was used to identify published literature relevant to the purpose of this review. There are several anatomical and functional similarities between the linea alba and musculoskeletal tendons. Because of this reason, many of the surgical principles for musculoskeletal tendon repair and ventral hernia repair overlap. Distribution of tension is the main driving principle for both procedures. Suture material and configuration are chosen to maximize tension distribution among the tissue edges, as seen in the standard of care multistrand repairs for musculoskeletal tendons, as well as in the small bites for laparotomy technique described in the STITCH trial. Physical therapy is also one of the mainstays of tendon repair, but surprisingly, is not routine in ventral hernia repair. The evidence surrounding physical therapy prehabilitation and rehabilitation protocols in other disciplines is significant. This review challenges the fact that these protocols are not routinely implemented for ventral hernia repair, and presents the rationale and feasibility for the routine practice of physical therapy in ventral hernia repair.

Personalized Computational Models of Tissue-Rearrangement in the Scalp Predict the Mechanical Stress Signature of Rotation Flaps.

To elucidate the mechanics of scalp rotation flaps through 3D imaging and computational modeling. Excessive tension near a wound or sutured region can delay wound healing or trigger complications. Measuring tension in the operating room is challenging, instead, noninvasive methods to improve surgical planning are needed. Multi-view stereo allows creation of 3D patient-specific geometries based on a set of photographs. The patient-specific 3D geometry is imported into a finite element (FE) platform to perform a virtual procedure. The simulation is compared with the clinical outcome. Additional simulations quantify the effect of individual flap parameters on the resulting tension distribution. Rotation flaps for reconstruction of scalp defects following melanoma resection in 2 cases are presented. Rotation flaps were designed without preoperative FE preparation. Tension distribution over the operated region. The tension from FE shows peaks at the base and distal ends of the scalp rotation flap. The predicted geometry from the simulation aligns with postoperative photographs. Simulations exploring the flap design parameters show variation in the tension. Lower tensions were achieved when rotation was oriented with respect to skin tension lines (horizontal tissue fibers) and smaller rotation angles. Tension distribution following rotation of scalp flaps can be predicted through personalized FE simulations. Flaps can be designed to reduce tension using FE, which may greatly improve the reliability of scalp reconstruction in craniofacial surgery, critical in complex cases when scalp reconstruction is essential for coverage of hardware, implants, and/or bone graft.

Single-Molecule Stretching Shows Glycosylation Sets Tension in the Hyaluronan-Aggrecan Bottlebrush

Large bottlebrush complexes formed from the polysaccharide hyaluronan (HA) and the proteoglycan aggrecan contribute to cartilage compression resistance and are necessary for healthy joint function. A variety of mechanical forces act on these complexes in the cartilage extracellular matrix, motivating the need for a quantitative description that links their structure and mechanical response. Studies using electron microscopy have imaged the HA-aggrecan brush but require adsorption to a surface, dramatically altering the complex from its native conformation. We use magnetic tweezers force spectroscopy to measure changes in extension and mechanical response of an HA chain as aggrecan monomers bind and form a bottlebrush. This technique directly measures changes undergone by a single complex with time and under varying solution conditions. Upon addition of aggrecan, we find a large swelling effect manifests when the HA chain is under very low external tension (i.e., stretching forces less than ∼1 pN). We use models of force-extension behavior to show that repulsion between the aggrecans induces an internal tension in the HA chain. Through reference to theories of bottlebrush polymer behavior, we demonstrate that the experimental values of internal tension are consistent with a polydisperse aggrecan population, likely caused by varying degrees of glycosylation. By enzymatically deglycosylating the aggrecan, we show that aggrecan glycosylation is the structural feature that causes HA stiffening. We then construct a simple stochastic binding model to show that variable glycosylation leads to a wide distribution of internal tensions in HA, causing variations in the mechanics at much longer length scales. Our results provide a mechanistic picture of how flexibility and size of HA and aggrecan lead to the brush architecture and mechanical properties of this important component of cartilage.

Adaptive Synchronization Control of Cable-Driven Parallel Robots With Uncertain Kinematics and Dynamics

Cable-driven parallel robots (CDPRs) are a new type of parallel robots with a mobile platform driven by several cables. The flexibility of the structure not only helps them perform better than traditional parallel robots, but also brings about the issues of model uncertainty and multicable coordination. To handle these problems, a novel adaptive synchronization control (ASC) scheme is proposed to suppress the uncertainties of kinematics and dynamics simultaneously, regulate the coordination motion of multiple cables, and finish high-precision tracking tasks. In the proposed scheme, apart from tracking error, a new synchronization error is introduced to describe the coordination motion relationship between adjacent cables. According to these defined errors, the kinematic and dynamic adaptation laws are designed through the linear expressions of kinematic and dynamic models, respectively. Finally, the ASC scheme is presented as well as a tension distribution algorithm. The tracking experiments are implemented on a redundantly actuated 3-degree-of-freedom CDPR with four cables. The proposed ASC scheme can effectively complete the correction of the model parameters by using the feedback of errors and enhance the tracking accuracy of each cable and the synchronization accuracy between all the cables significantly, thereby ultimately improving the control performance of the mobile platform.