A new mortise and tenon timber structure and its automatic construction system

Qiao, Wentao; Wang, Zexiong; Wang, Dong; Zhang, Long

doi:10.1016/j.jobe.2021.103369

Cited by 5 publications

(5 citation statements)

References 26 publications

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“…Surface preparations by the squirrels allow the nuts to be “pressure fitted” between the two plant twigs in a way similar to the mortise-tenon structure in ancient Chinese architecture (Qiao et al, 2021) (Figure 2) . The carved nuts are inlayed between plant twigs (0.10-0.60 cm in diameter) intersecting at specific angles (25-40°) on various understory plants (Figure 3) , including small trees and shrubs, sometimes lianas, bamboos or dead trees, and even occasionally big petioles of palms or trees (Figures 1j-n, Supplementary Table 2) .…”

Section: Resultsmentioning

confidence: 99%

Smart squirrels use a mortise-tenon structure to fix nuts on understory twigs

Lian

Spence

et al. 2022

Preprint

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Squirrels of temperate zones commonly store nuts or seeds under leaf litter, in hollow logs or even in holes in the ground; however, in humid rainforests, it is an evolutionary challenge for squirrels to hang elliptical or oblate nuts securely on trees to minimize germination or fungal infection. Here, we report a unique behaviour used by two species of small flying squirrels (Hylopetes phayrei electilis(G. M. Allen, 1925) andHylopetes alboniger(Hodgson, 1870)) to cache nuts on Hainan Island. Squirrels intentionally carved grooves encircling ellipsoid nuts or distributed on the bottom of oblate nuts and used these grooves to fix nuts tightly between small twigs 0.1-0.6 cm in diameter and connected at angles of 25-40°. The resulting structures were similar to the mortise-tenon joint of ancient Chinese architecture. Cache sites were on small plants located 10-25 m away from the closest potentially nut-producing tree, a behaviour that likely deters discovery and consumption of the nuts by other animals. Their ability to shape individual nuts to store them more securely suggests it is a smart behavior, which is likely formed by the adaption to life in humid tropical rainforests to guarantee food supply and impacts the distribution of tree species.

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Section: Resultsmentioning

confidence: 99%

Smart squirrels use a mortise-tenon structure to fix nuts on understory twigs

Lian

Spence

et al. 2022

Preprint

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“…. θ 3 (t) =a 31 +2a 32 t+3a 33 t 2 , (9) .. θ 1 (t) = 2a 12 + 6a 13 t, (10) .. θ 2 (t) = 2a 22 + 6a 23 t+12a 24 t 2 +20a 25 t 3 , (11) ..…”

Section: -5-3 Piecewise Polynomial Interpolationmentioning

confidence: 99%

“…Woodworking manipulators are convenient, which can realize the free movement and rotation of four-head highspeed electric spindles in the workspace to drill and mill wooden structures. However, their unstable operation and long running times pose challenges to the wood processing process, leading to high accident rates and poor efficiency [10,11]. Appropriate trajectory interpolation algorithms can improve manipulator's operational stability, and the use of intelligent optimization algorithms for time-optimal trajectory planning can improve the manipulator's efficiency.…”

Section: Introductionmentioning

confidence: 99%

Time-Optimal Trajectory Planning for Woodworking Manipulators Using an Improved PSO Algorithm

Chen,

Zhang,

2023

Applied Sciences

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Woodworking manipulators are applied in wood processing to promote automatic levels in the wood industry. However, traditional trajectory planning results in low operational stability and inefficiency. Therefore, we propose a method combining 3-5-3 piecewise polynomial (composed of cubic and quintic polynomials) interpolation and an improved particle swarm optimization (PSO) algorithm to study trajectory planning and time optimization of woodworking manipulators. In trajectory planning, we conducted the kinematics analysis to determine the position information of joints at path points in joint space and used 3-5-3 piecewise polynomial interpolation to fit a point-to-point trajectory and ensure the stability. For trajectory time optimization, we propose an improved PSO that adapts multiple strategies and incorporates a golden sine optimization algorithm (Gold-SA). Therefore, the proposed improved PSO can be called GoldS-PSO. Using benchmark functions, we compared GoldS-PSO to four other types of PSO algorithms and Gold-SA to verify its effectiveness. Then, using GoldS-PSO to optimize the running time of each joint, our results showed that GoldS-PSO was superior to basic PSO and Gold-SA. The shortest running time obtained by using GoldS-PSO was 47.35% shorter than before optimization, 8.99% shorter than the basic PSO, and 6.23% shorter than the Gold-SA, which improved the running efficiency. Under optimal time for GoldS-PSO, our simulation results showed that the displacement and velocity of each joint were continuous and smooth, and the acceleration was stable without sudden changes, proving the method’s feasibility and superiority. This study can serve as the basis for the motion control system of woodworking manipulators and provide reference for agricultural and forestry engineering optimization problems.

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“…As a natural and renewable material, timber has been widely used in the building and furniture industries [ 1 ]. In these industries, many wooden parts are joined by connectors such as glue and screws.…”

Section: Introductionmentioning

confidence: 99%

A comprehensive mortise and tenon structure selection method based on Pugh’s controlled convergence and rough Z-number MABAC method

Shang

Chen

et al. 2023

PLoS ONE

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Mortise and tenon joints are widely used in the building and furniture industries because of their excellent mechanical and eco-friendly properties. In real-life cases, there are usually many available alternative structures for a joint area, it is a challenge to select a proper structure from massively available alternatives. This paper aims to select a proper multiple attribute decision-making method based on massive alternatives and unreliable, uncertain and subjective information. Pugh’s controlled convergence, rough number, Z-number, consistency theory and Shannon entropy are integrated and proposed an improved rough Z-number Multi-Attributive Border Approximation Area Comparison (MABAC) method. Firstly, Pugh’s controlled convergence is a selection method, simple and rapid, presented in the first phase to eliminate most of the alternatives. In the second phase, an integrated method is proposed. The consistency theory, distance measurement and the Z-number are initially aggregated to calculate the expert weight. The entropy method is then presented to determine the criteria weight. The alternatives are then ranked and the optimal mortise and tenon joint is selected based on the rough Z-number MABAC method. A real-life case is presented, and the proposed method is implemented in the joint of a bucket cabinet. Finally, the efficiency and effectiveness of the proposed method are proved by the case, sensitivity analysis and related comparisons.

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A new mortise and tenon timber structure and its automatic construction system

Cited by 5 publications

References 26 publications

Smart squirrels use a mortise-tenon structure to fix nuts on understory twigs

Smart squirrels use a mortise-tenon structure to fix nuts on understory twigs

Time-Optimal Trajectory Planning for Woodworking Manipulators Using an Improved PSO Algorithm

A comprehensive mortise and tenon structure selection method based on Pugh’s controlled convergence and rough Z-number MABAC method

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