Attitude Adjustments Research Articles

Adaptive Pitch-Tracking Control with Dynamic and Static Gains for Remotely Operated Towed Vehicles

The pitch angle regulation in Remotely Operated Towed Vehicles (ROTVs) is essential to ensure the robustness of emitted signals within the maritime surveillance domain. Characterized by inherent nonlinear dynamics and stochastic uncertainties, the pitch angle model poses significant challenges to conventional tracking controls relying on linearization. This study introduces an adaptive pitch-control algorithm designed for ROTVs, which adeptly manages nonlinear dynamics as well as unmeasurable states through a synergistic integration of dynamic and static gains. A key feature of our approach is the incorporation of a high-order observer that adeptly estimates the system’s unmeasurable states, thereby enhancing control precision. Our proposed algorithm greatly exceeds traditional PID and fuzzy PID methods in both settling time and steady-state error, particularly in high-order nonlinear and unmeasurable state scenarios. Compared to sliding mode control, the proposed control strategy improved the settling time by 74% and the steady-state error was enhanced from 10−6 to 10−8, as confirmed by numerical simulations. The efficacy of the algorithm in achieving the desired tracking trajectories highlights its potential for deep-water operations and fine-tuned attitude adjustments for ROTVs.

Research on Precise Attitude Measurement Technology for Satellite Extension Booms Based on the Star Tracker

This paper reports the successful application of a self-developed, miniaturized, low-power nano-star tracker for precise attitude measurement of a 5-m-long satellite extension boom. Such extension booms are widely used in space science missions to extend and support payloads like magnetometers. The nano-star tracker, based on a CMOS image sensor, weighs 150 g (including the baffle), has a total power consumption of approximately 0.85 W, and achieves a pointing accuracy of about 5 arcseconds. It is paired with a low-cost, commercial lens and utilizes automated calibration techniques for measurement correction of the collected data. This system has been successfully applied to the precise attitude measurement of the 5-m magnetometer boom on the Chinese Advanced Space Technology Demonstration Satellite (SATech-01). Analysis of the in-orbit measurement data shows that within shadowed regions, the extension boom remains stable relative to the satellite, with a standard deviation of 30′′ (1σ). The average Euler angles for the “X-Y-Z” rotation sequence from the extension boom to the satellite are [−89.49°, 0.08°, 90.11°]. In the transition zone from shadow to sunlight, influenced by vibrations and thermal factors during satellite attitude adjustments, the maximum angular fluctuation of the extension boom relative to the satellite is approximately ±2°. These data and the accuracy of the measurements can effectively correct magnetic field vector measurements.

Innovative design and development of attitude determination and control systems for CubeSats with reaction wheels

Attitude determination and control systems (ADCS) represent a critical facet of CubeSat missions, orchestrating the precise orientation and stabilization of these small satellites in the space environment. This paper presents a comprehensive design and development of an ADCS tailored for CubeSats, harnessing a reaction wheel system to deliver a cost-effective and dependable solution for small satellite applications. The research begins by elucidating the requisites and specifications for the ADCS and then delves into the design phase, complemented by intricate modelling and simulation employing MATLAB Simulink and the Webots Simulator. The results of this study underscore the exceptional performance of the proposed ADCS configuration, leveraging the reaction wheel model. This system demonstrates an unparalleled capacity to achieve precise and controlled attitude adjustments, well within the defined parameters. Furthermore, this research underscores the pivotal role played by efficient system design, meticulous simulation, and rigorous testing in the triumphant implementation of ADCS, greatly enhancing CubeSat missions and their contributions to the realm of space exploration and technology innovation. This comprehensive approach to the design and testing of an ADCS for CubeSats ensures that these diminutive satellites continue to make significant strides in space missions, paving the way for an exciting future of space research and technology development.

Safety Analysis of Initial Separation Phase for AUV Deployment of Mission Payloads

This study verifies the effects of deployment parameters on the safe separation of Autonomous Underwater Vehicles (AUVs) and mission payloads. The initial separation phase is meticulously modeled based on computational fluid dynamics (CFD) simulations employing the cubic constitutive Shear Stress Transport (SST) k-ω turbulence model and overset grid technologies. This phase is characterized by a 6-degree-of-freedom (6-DOF) framework incorporating Dynamic Fluid-Body Interaction (DFBI), supported by empirical validation. The SST k-ω turbulence model demonstrates superior performance in managing flows characterized by adverse pressure gradients and separation. DFBI entails computationally modeling fluid–solid interactions during motion or deformation. The utilization of overset grids presents several advantages, including enhanced computational efficiency by concentrating computational resources solely on regions of interest, simplified handling of intricate geometries and moving bodies, and adaptability in adjusting grids to accommodate changing simulation conditions. This research analyzes mission payloads’ trajectories and attitude adjustments after release from AUVs under various cruising speeds and initial release dynamics, such as descent and angular velocities. Additionally, this study evaluates the effects of varying ocean currents at different depths on separation safety. Results indicate that the interaction between AUVs and mission payloads during separation increases under higher navigational speeds, reducing the separation speed and degrading the stability. As the initial drop velocities increase, fast transition through the AUV’s immediate flow field promotes separation. The core of this process is the initial pitch angle management upon deployment. Optimizing initial pitching angular velocity prolongs the time for mission payloads to reach their maximum pitch angle, thus decreasing horizontal displacement and improving separation safety. Deploying AUVs at greater depths alleviates the influence of ocean currents, thereby reducing disturbances during payload separation.

Control of Self-Winding Microrobot Using an Electromagnetic Drive System: Integration of Movable Electromagnetic Coil and Permanent Magnet.

Achieving precise control over the motion position and attitude direction of magnetic microrobots remains a challenging task in the realm of microrobotics. To address this challenge, our research team has successfully implemented synchronized control of a microrobot's motion position and attitude direction through the integration of electromagnetic coils and permanent magnets. The whole drive system consists of two components. Firstly, a stepper motor propels the delta structure, altering the position of the end-mounted permanent magnet to induce microrobot movement. Secondly, a programmable DC power supply regulates the current strength in the electromagnetic coil, thereby manipulating the magnetic field direction at the end and influencing the permanent magnet's attitude, guiding the microrobot in attitude adjustments. The microrobot used for performance testing in this study was fabricated by blending E-dent400 photosensitive resin and NdFeB particles, employing a Single-Layer 4D Printing System Using Focused Light. To address the microrobot drive system's capabilities, experiments were conducted in a two-dimensional and three-dimensional track, simulating the morphology of human liver veins. The microrobot exhibited an average speed of 1.3 mm/s (movement error ± 0.5 mm). Experimental results validated the drive system's ability to achieve more precise control over the microrobot's movement position and attitude rotation. The outcomes of this study offer valuable insights for future electromagnetic drive designs and the application of microrobots in the medical field.

Novel Operation Mechanism and Multifunctional Applications of Bubble Microrobots.

Microrobots have emerged as powerful tools for manipulating particles, cells, and assembling biological tissue structures at the microscale. However, achieving precise and flexible operation of arbitrary-shaped microstructures in 3D space remains a challenge. In this study, three novel operation methods based on bubble microrobots are proposed to enable delicate and multifunctional manipulation of various microstructures. These methods include 3D turnover, fixed-point rotation, and 3D ejection. By harnessing the combined principles of the effect of the heat flow field and surface tension of an optothermally generated bubble, the bubble microrobot can perform tasks such as flipping an SIA humanoid structure, rotating a bird-like structure, and launching a hollow rocket-like structure. The proposed multi-mode operation of bubble microrobots enables diverse attitude adjustments of microstructures with different sizes and shapes in both 2D and 3D spaces. As a demonstration, a biological microenvironment of brain glioblastoma is constructed by the bubble microrobot. The simplicity, versatility, and flexibility of this proposed method hold great promise for applications in micromanipulation, assembly, and tissue engineering.

Dynamics and control of sun-facing diffractive solar sails in displaced orbit for asteroid deflection

A gravity tractor spacecraft propelled by a diffractive sail tracking a displaced orbit offers a potential option for deflecting near-Earth asteroids. This study delves into the preliminary dynamics, evaluates the deflection capabilities, and investigates the stability and control of the diffractive sail on the displaced orbit near the asteroid. Unlike reflective sails, diffractive solar sails generate tangential radiation pressure force, offering multiple advantages. These include the elimination of tilt attitude requirements, no offset angle restrictions from the target asteroid's flight direction, and superior deflection performance with an equivalent area-to-mass ratio when the diffraction angle surpasses 50deg. To maintain position, a controllable diffractive sail model using spatial light modulators, coupled with a feedback control law, is proposed. This control design stabilizes the periodic displaced orbit without necessitating tilt attitude adjustments towards the sun, as validated by our numerical simulations.

Large gear structure assembly method based on uncalibrated image visual servo guidance.

The reliability of the transmission system hinges significantly on the assembly quality of its main component, the large gear structures. However, the traditional approach of employing manual lifting presents a host of challenges, such as high assembly complexity and lowered efficiency, rendering the overall assembly process notably arduous. In this study, a large gear structure assembly method based on uncalibrated image visual servo guidance is proposed. Comprising three modules, the approach involves constructing a task function for projective homography, estimating the image Jacobian matrix, and designing an adaptive servo controller. This methodology facilitates the mapping of changes in gear images to the motion of the end-effector in the parallel mechanism. Consequently, the system dynamically guides the end-effector to achieve the required attitude adjustments in the gear assembly in response to changes in the image features. Experimental results demonstrate that the method proposed surpasses alternative approaches, simultaneously exhibiting a significant enhancement in assembly efficiency. The method has a wide application prospect in the field of automated assembly of large gear structures.

The detection of self–group conflicts in exercise behaviors differs with social network centrality: ERP evidence

BackgroundThe influence of social norms on exercise behaviors has been explored in studies over the years. However, little is known about whether an individual’s role (central or peripheral) in his or her social network, which is associated with social skills, could shift his or her susceptibility to normative effects on exercise behaviors. To that end, event-related potentials (ERPs) were recorded to examine the underlying cognitive mechanism of the effects of network centrality on normative social influence. MethodsWe manipulated network centrality by assigning participants to exercise support groups, with group members who were their nominated friends (high centrality) or nonnominated classmates (low centrality). Participants were asked to evaluate their willingness to engage in various exercises, after viewing discrepant group ratings (peer influence) or not viewing (no-influence). ResultsPeer influence evoked a larger negative-going feedback-related negativity (FRN) wave, which was linked to automatic social conflict detection, and a larger positive-going P3 wave, which was linked to subsequent conformity behavioral changes. However, effects on the FRN, not the P3, were observed only in the high-centrality group. ConclusionOur results highlight the important roles of network centrality in encoding self–group exercise attitude discrepancy rather than in decision-making regarding exercise attitude adjustments. Interventions aimed at promoting exercise behaviors should be considered in a broader social environmental framework.

Attitude control for a full-scale flexible electric solar wind sail spacecraft on heliocentric and displaced non-Keplerian orbits

The electric solar wind sail (E-sail) spacecraft is a fuel-free propulsion system with promising potential in deep space explorations and solar activity monitoring missions. It is challenging to conduct attitude control for a full-scale flexible E-sail spacecraft due to its complex dynamical characteristics, including the spatial multi-scale, high-speed spinning, and large deformations. In this work, a double-loop attitude control strategy for the flexible E-sail spacecraft with high accuracy and efficiency is proposed. The E-sail spacecraft is firstly modeled by the referenced nodal coordinate formulation, where the rotations are described by the Lie group approach. A state-feedback controller developed from the Lyapunov stability theory is prescribed as the inner loop. The gain is obtained by solving a semidefinite programming problem with linear matrix inequality constraints, which is globally optimal and numerically reliable. A multi-variable proportional-integral-derivative controller is then introduced as the outer loop for flexibly enhancing the control performance. Several missions of the E-sail spacecraft, including attitude maneuvers on heliocentric and displaced non-Keplerian orbits, are studied to show that the desired attitude adjustments are accurately and efficiently achieved without exciting high-frequency oscillations. The double-loop control strategy has great prospects in designing and implementing orbital transformation and long-term stable Sun-orbiting missions.

Optimal Collaborative Motion Planning of Dual Boom Cranes for Transporting Payloads to Desired Positions and Attitudes

With the increasing demands of high-precision hoisting, a growing number of to-be-hoisted large-scale heavy payloads <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">not only</i> need accurate positioning transportation, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">but also</i> require specific attitude adjustments, which mostly relies on dual boom cranes (DBCs) in practice due to their powerful capability. To achieve effective non-horizontal payload hoisting, the two booms of DBCs should reach different positions while guaranteeing safety, high efficiency, and energy conservation, which makes coordinated boom motions particularly difficult. To this end, an optimal collaborative motion planning method for DBCs is proposed in this paper <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">without</i> any linearization, which realizes fast, accurate, and energy-saving payload transportation with swing suppression. To the best of our knowledge, the proposed method provides the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">first</i> solution for DBCs to transport payloads to the desired non-horizontal attitudes, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">simultaneously</i> achieves comprehensive optimization of multiple performance indicators, including transportation time, energy consumption, etc., on the premise of safety. On the theoretical side, novel collaborative auxiliary signal construction and parametric design guarantee the coordination of boom motions, and the solving process of optimal trajectories is simplified through elaborate convex optimization problem reformulation and analysis. At last, the effectiveness and adaptability of the proposed method are verified by hardware experiments under different working requirements.

Tracking error prediction informed motion control of a parallel machine tool for high-performance machining

Parallel machine tools (PMTs) are suitable for machining parts with complex surface features, owing to their advantages in providing flexible attitude adjustments and quick dynamic responses. However, due to the characteristics of the multiple-axis coupling motions and nonlinear dynamics, how to achieve high-efficiency and high-quality machining using PMTs remains a challenging issue encountered in the field. To solve this problem, in this study, the tracking error generation mechanism for PMTs is originally disclosed, which indicates that the driving limb's tracking error includes the error caused by the time-varying load, and that caused by the input signal. Accordingly, an integrated control method combining real-time dynamic feedforward and feedrate scheduling is proposed for reducing these two parts of the tracking errors. A stepwise identification method that can decouple the friction parameters and inertial parameters is designed for real-time dynamic feedforward control. In addition, by establishing systematic machining quality constraints related to the PMT's dynamic properties, a feedrate scheduling method for complex spline toolpaths is put forward. Finally, toolpath tracking and machining comparison experiments are conducted with a commercial ISG computer numerical control (CNC) kernel to validate the advantages of the proposed control method. The experimental results demonstrate that the proposed integrated control method can effectively improve the machining efficiency and machining quality. In summary, this study analytically formulates a tracking error prediction model for PMTs, and proposes an integrated control method for high-performance machining. The findings of this study provide a feasible way to improve the performance of PMTs, and to further promote their popularization and application in industry.

Innovating Vocational Resilience: Getting a Second Start at Work through the Ignatian Examen

The Ignatian Examen is a tool that can build vocational resilience for social workers. It has five components: 1) praying for light or becoming aware of the presence of God, 2) gratefully reviewing the events of the day, 3) reviewing the feelings and emotions that surface when events are brought to mind, 4) choosing one of those feelings, either positive or negative, and praying from it, and 5) looking toward the future. Although it is often used as a bedtime prayer, St. Ignatius of Loyola designed the Examen to occur twice, at noon and after supper, with an additional remembrance of the evening Examen upon rising. The noon Examen may actually be the most important practice to build vocational resilience for social workers because the noon Examen allows for calming the workday and for making course corrections and attitude adjustments as needed.

Cloud-Based Experimental Platform for the Space-Ground Integrated Network

The space-ground integrated network (SGIN) is an important direction of future network development and is expected to play an important role in edge computing for the Internet of Things (IoT). Through integration with an SGIN, IoT applications can provide services with long-distance and wide-coverage features. However, SGINs are typical large-scale and time-varying networks for which new network technologies, protocols, and applications must be rigorously evaluated and validated. Therefore, a reliable experimental platform is necessary for SGINs. This paper presents a cloud-based experimental platform for the SGIN context named SGIN-Stack. First, the architecture of SGIN-Stack, which combines the Systems Tool Kit (STK) and OpenStack, is described. Based on this architecture, a seamless linkage between OpenStack and STK is achieved to realize synchronous, dynamic, and real-time network emulation for an SGIN, and the dynamic differential compensation technology and a random number generation algorithm are applied to improve the emulation accuracy for satellite links. Finally, an emulation scenario is constructed that includes six space-based backbone nodes, sixty-six space-based access nodes, and a ground station. Based on this emulation scenario, experiments concerning the satellite link delays, bit error ratio (BER), and throughput are carried out to prove the high fidelity of our SGIN-Stack platform. Emulation experiments involving satellite orbital maneuvers and attitude adjustments show that SGIN-Stack can be used for dynamic and real-time SGIN emulation.

Attitude adjustments after global health inter-professional student team experiences.

How medical inter-professional (IP) education should be introduced to students is still a matter of research. We evaluated IP student attitudes before and after a busy “hands-on” clinical experience.During 3 separate trips, first/second year medical and physician assistant students and third/fourth year nursing students traveled to Central America to work together for 1 week in an underserved clinical setting. Student opinions on inter-professional education were obtained before and after Brigade-1 using the Readiness for Inter-professional Learning Scale validated questionnaire. From these results, a modified version of the survey was developed that included quantitative and qualitative responses. For brigades-2 and -3, students received this modified version of the survey pre and post brigade. Quantitative data was analyzed via paired student t test, and qualitative data was analyzed to identify emerging themes using constant comparative methodology by three separate investigators.No significant quantitative differences between IP student groups were observed in their evaluation of the importance of inter-professional education either before or after the brigades. Qualitative data noted pre-brigade expectations of positive IP, experiential and patient-centered cultural learning. Pre- and post-brigade student perspectives maintained a strong belief that high functioning IP care benefited the patient. Post-brigade perspectives revealed a shift in attitude from purely positive expectations to more practical aspects of teamwork, respect, and interpersonal relationships.Students believe that patient care benefits from IP collaboration. After a busy clinical experience requiring collaboration, students realized that functional teams require appropriate skills, roles, and respectful interpersonal relationships.

Numerical investigation on the thermal performance of Alpha Magnetic Spectrometer main radiators under the operation of International Space Station

The thermal environment of the space-borne instruments can be affected by their carriers. Investigation on those thermal effects has great importance for those payloads operating safely and stably. In the current work, the influences of the operation of International Space Station flight attitude adjustment on the thermal performance of the Alpha Magnetic Spectrometer main radiators are studied by numerical simulations. For that purpose, the thermal network model is developed and validated by the theoretical calculation from the mathematical model, based on which, the external heat flux absorbed and the temperature response characteristics under the three most frequent attitude adjustments are further studied. By the results, the error between the two models is less than 18.2% which proves the validation of the developed numerical model. The external heat flux varies obviously when changing the flight attitude and even reaches its maximum of 480 W/m2. The temperatures respond accordingly and may even cause the temperature anomalies in 44.8% of the selected cases with the minimum occurrence time of 6235 s. Moreover, the areas with the most drastic temperature variations are always located at the upper-right and the bottom positions of AMS main radiators, which is independent of the flight attitude adjustment.

Low Earth Orbit Plasma Wake Shaping and Applications to On-Orbit Proximity Operations

A parametric investigation of plasma wake geometry is conducted to determine the applicability of Coulomb actuation to resident space objects (RSOs) in low earth orbit (LEO). The use of Coulomb forces could provide a touchless means to achieve the relative position and attitude adjustments between close-proximity objects on orbit. Theoretical models developed for techniques in the geosynchronous earth orbit (GEO) regime indicate that Coulomb actuation could facilitate on-orbit proximity operations in a highly fuel- and power-efficient manner. In LEO, however, only the plasma parameters in the wakes behind orbiting objects are a promising region for Coulomb actuation applications. These physical phenomena investigated by the charging hazards and wake studies (CHAWS), space experiments with particle accelerators (SEPAC), and other on-orbit experiments exhibit substantially decreased plasma density relative to the surroundings. This investigation considers the wake which forms behind objects of various potentials and cross-sectional areas, particularly focusing on methods of enhancing the wake with negligible changes in the objects' area, and therefore their mass. Experimental results are presented and compared with previous theoretical, numerical, and experimental works. The size of a wake formed by an uncharged object is shown to depend on its cross-sectional area. However, the same object charged to a positive potential generates a substantially larger wake. Additional experimental results indicate that a positively charged, sparse structure with similar dimensions, but significantly less cross-sectional area forms a wake similar to the previous, solid object charged to the same level. This indicates that a large wake can be generated without significantly increasing the mass or area-dependent perturbations such as the drag and the solar radiation pressure. These results increase the applicability of Coulomb actuation in LEO by enhancing the region in which the technique is feasible.

Thermal analysis on Alpha Magnetic Spectrometer main radiators under the flight attitude adjustment of International Space Station

Thermal environments of the spaceborne instruments applied for space experiments and space explorations are affected by the maneuvers of the carrier itself, those effects should be taken into account for the designing, manufacturing and long-term stable operation of the spaceborne instruments. In this paper, the mathematical model with three angle variables is established to determine the thermal radiation processes under various attitudes of International Space Station. The results reveal that only the variations of two angles can affect the radiative heat transfer of the Alpha Magnetic Spectrometer main radiators. Based on that, the thermal impacts of the International Space Station attitude adjustments on the main radiators of Alpha Magnetic Spectrometer are numerically investigated in thermal network method, the variation regularities of the external heat flux and the corresponding temperature response are further determined. Results show that the external heat flux has the largest variation at the extreme β angle with the maximum difference of 384 W/m2 on RAM radiator of Alpha Magnetic Spectrometer. After the maneuver of the attitude adjustment, a total of 42% cases have the possibility of temperature anomalies with the occurrence time ranging from 6235 s to 73897 s.

Major tectonic rotation along an oceanic transform zone, northern Iceland: Evidence from field and paleomagnetic investigations

We provide structural and paleomagnetic evidence for major distributed rotational shear adjacent to and including the active Húsavík-Flatey transform fault in the southern part of the Tjörnes Fracture Zone of north Iceland. In the Flateyjarskagi peninsula immediately south of the fault, dike and bedding trends gradually change over about 11 km in approaching the transform fault main trace. In map view this pattern is seen as a progressive clockwise curvature of structural elements that equals or in some cases exceeds 90°. We present paleomagnetic analyses that verify large clockwise rotations of the same order as the curvature of structural elements observed. We compare our field and paleomagnetic observations with results from careful analog modeling that demonstrate how regional curvature of structures results from distributed strain that dominates the early stages of transform shear deformation, prior to the appearance of a transform fault system comprised of discrete shears. Our paleomagnetic results were obtained from one relatively undisturbed reference site, and three sites of deformed rocks in Flateyjarskagi and two in Tjörnes peninsula. These results indicate large vertical-axis rotations, and the progressive deflection of dike trends throughout northern Flateyjarskagi also serves as a separate quantitative estimate of vertical-axis rotation. The clockwise vertical-axis rotation estimates of 71°–97° from dikes are less than those deduced from paleomagnetism, but the order of magnitude is correct and we attribute the differences as mainly reflecting imperfect bed attitude adjustments used in analyses. The problem is typical for deformed rocks from high-latitude sites with steeply inclined paleomagnetic vectors. We consider our field measurements of dikes as more accurate indicators of true tectonic rotation. This regional deformation of Miocene rocks occurred early in the evolution of the TFZ transform, probably beginning ca. 7 Ma, when an older rift zone present in western North Iceland jumped to its present NVZ location in northeast Iceland. The early deformations involved shear strain distributed over a region about 20-km broad and produced the curved structures. This phase was followed by the sequential development of more narrowly distributed discrete shears, generating the initial Húsavík-Flatey transform fault.

A Normal Sensor Calibration Method Based on an Extended Kalman Filter for Robotic Drilling.

To enhance the perpendicularity accuracy in the robotic drilling system, a normal sensor calibration method is proposed to identify the errors of the zero point and laser beam direction of laser displacement sensors simultaneously. The procedure of normal adjustment of the robotic drilling system is introduced firstly. Next the measurement model of the zero point and laser beam direction on a datum plane is constructed based on the principle of the distance measurement for laser displacement sensors. An extended Kalman filter algorithm is used to identify the sensor errors. Then the surface normal measurement and attitude adjustments are presented to ensure that the axis of the drill bit coincides with the normal at drilling point. Finally, simulations are conducted to study the performance of the proposed calibration method and experiments are carried out on a robotic drilling system. The simulation and experimental results show that the perpendicularity of the hole is within 0.2°. They also demonstrate that the proposed calibration method has high accuracy of parameter identification and lays a basis for high-precision perpendicularity accuracy of drilling in the robotic drilling system.