机构运动学与动力学分析与建模 Ch00-2质量刚体的在坐标系下运动Part3
2.2.3 欧拉方程 Euler equation - 2
- 进而分析 H ⃗ Σ M F = m t o t a l ⋅ R ⃗ G F × V ⃗ G F + ∫ ( R ⃗ G P i F ⋅ R ⃗ G P i F ) ω ⃗ M F d m i − ∫ ( R ⃗ G P i F ⋅ ω ⃗ M F ) R ⃗ G P i F d m i \vec{H}_{\Sigma _{\mathrm{M}}}^{F}=m_{\mathrm{total}}\cdot \vec{R}_{\mathrm{G}}^{F}\times \vec{V}_{\mathrm{G}}^{F}+\int{\left( \vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}\cdot \vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F} \right) \vec{\omega}_{\mathrm{M}}^{F}}\mathrm{d}m_{\mathrm{i}}-\int{\left( \vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}\cdot \vec{\omega}_{\mathrm{M}}^{F} \right) \vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}}\mathrm{d}m_{\mathrm{i}} H ΣMF=mtotal⋅R GF×V GF+∫(R GPiF⋅R GPiF)ω MFdmi−∫(R GPiF⋅ω MF)R GPiFdmi,有:
H ⃗ Σ M F = m t o t a l ⋅ R ⃗ G F × V ⃗ G F + ∫ ( R ⃗ G P i F T R ⃗ G P i F ⋅ E 3 × 3 − R ⃗ G P i F R ⃗ G P i F T ) d m i ⋅ ω ⃗ M F = m t o t a l ⋅ R ⃗ G F × V ⃗ G F + [ I ] Σ M / G F ⋅ ω ⃗ M F H ⃗ Σ M / G F = H ⃗ Σ M F − m t o t a l ⋅ R ⃗ G F × V ⃗ G F = [ I ] Σ M / G F ⋅ ω ⃗ M F \begin{split} &\vec{H}_{\Sigma _{\mathrm{M}}}^{F}=m_{\mathrm{total}}\cdot \vec{R}_{\mathrm{G}}^{F}\times \vec{V}_{\mathrm{G}}^{F}+\int{\left( {\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}}^{\mathrm{T}}\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}\cdot E^{3\times 3}-\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}{\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}}^{\mathrm{T}} \right)}\mathrm{d}m_{\mathrm{i}}\cdot \vec{\omega}_{\mathrm{M}}^{F} =m_{\mathrm{total}}\cdot \vec{R}_{\mathrm{G}}^{F}\times \vec{V}_{\mathrm{G}}^{F}+\left[ I \right] _{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F}\cdot \vec{\omega}_{\mathrm{M}}^{F} \\ &\vec{H}_{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F}=\vec{H}_{\Sigma _{\mathrm{M}}}^{F}-m_{\mathrm{total}}\cdot \vec{R}_{\mathrm{G}}^{F}\times \vec{V}_{\mathrm{G}}^{F}=\left[ I \right] _{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F}\cdot \vec{\omega}_{\mathrm{M}}^{F} \end{split} H ΣMF=mtotal⋅R GF×V GF+∫(R GPiFTR GPiF⋅E3×3−R GPiFR GPiFT)dmi⋅ω MF=mtotal⋅R GF×V GF+[I]ΣM/GF⋅ω MFH ΣM/GF=H ΣMF−mtotal⋅R GF×V GF=[I]ΣM/GF⋅ω MF
则相对于质心点 G G G 存在:
{ M ⃗ Σ M / G F = [ I ] Σ M / G F α ⃗ M F + ω ⃗ M F × ( [ I ] Σ M / G F ⋅ ω ⃗ M F ) [ I ] Σ M / G F = ∫ ( R ⃗ G P i F T R ⃗ G P i F ⋅ E 3 × 3 − R ⃗ G P i F R ⃗ G P i F T ) d m i F ⃗ G F = m t o t a l a ⃗ G F \begin{cases} \vec{M}_{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F}=\left[ I \right] _{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F}\vec{\alpha}_{\mathrm{M}}^{F}+\vec{\omega}_{\mathrm{M}}^{F}\times \left( \left[ I \right] _{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F}\cdot \vec{\omega}_{\mathrm{M}}^{F} \right)\\ \left[ I \right] _{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F}=\int{\left( {\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}}^{\mathrm{T}}\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}\cdot E^{3\times 3}-\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}{\vec{R}_{\mathrm{GP}_{\mathrm{i}}}^{F}}^{\mathrm{T}} \right)}\mathrm{d}m_{\mathrm{i}}\\ \vec{F}_{\mathrm{G}}^{F}=m_{\mathrm{total}}\vec{a}_{\mathrm{G}}^{F}\\ \end{cases} ⎩ ⎨ ⎧M ΣM/GF=[I]ΣM/GFα MF+ω MF×([I]ΣM/GF⋅ω MF)[I]ΣM/GF=∫(R GPiFTR GPiF⋅E3×3−R GPiFR GPiFT)dmiF GF=mtotala GF - 对 H ⃗ Σ M / O F \vec{H}_{\Sigma _{\mathrm{M}}/\mathrm{O}}^{F} H ΣM/OF进一步推导(分析 [ I ] Σ M / G F \left[ I \right] _{\Sigma _{\mathrm{M}}/\mathrm{G}}^{F} [I]ΣM/GF),可得:
H ⃗ Σ M / O F = ∑ i N R ⃗ O P i F × P ⃗ P i F = ∑ i N m P i ⋅ R ⃗ O P i F × ( V ⃗ O F + ω ⃗ F × R ⃗ O P i F ) = ∑ i N m P i ⋅ R ⃗ ~ O P i F ⋅ ( ω ⃗ ~ F ⋅ R ⃗ O P i F ) + ∑ i N m P i ⋅ R ⃗ ~ O P i F ⋅ V ⃗ O F = ∑ i N m P i ⋅ [ I ^ J ^ K ^ ] T [ 0 − z O P i F y O P i F z O P i F 0 − x O P i F − y O P i F x O P i F 0 ] ⋅ [ I ^ J ^ K ^ ] T ( [ 0 − w z P i F w y P i F w z P i F 0 − w x P i F − w y P i F w x P i F 0 ] ⋅ [ x O P i F y O P i F z O P i F ] ) + m t o t a l ⋅ R ⃗ ~ O G F ⋅ V ⃗ O F = ∑ i N m P i ⋅ [ I ^ J ^ K ^ ] T [ [ ( y O P i F ) 2 + ( z O P i F ) 2 ] w x P i F − ( x O P i F y O P i F ) w y P i F − ( x O P i F z O P i F ) w z P i F − ( y O P i F x O P i F ) w x P i F + [ ( x O P i F ) 2 + ( z O P i F ) 2 ] w y P i F − ( y O P i F z O P i F ) w z P i F − ( z O P i F x O P i F ) w x P i F − ( z O P i F y O P i F ) w y P i F + [ ( x O P i F ) 2 + ( y O P i F ) 2 ] w z P i F ] + m t o t a l ⋅ R ⃗ ~ O G F ⋅ V ⃗ O F = ∑ i N m P i ⋅ [ I ^ J ^ K ^ ] T [ ( y O P i F ) 2 + ( z O P i F ) 2 − x O P i F y O P i F − x O P i F z O P i F − y O P i F x O P i F ( x O P i F ) 2 + ( z O P i F ) 2 − y O P i F z O P i F − z O P i F x O P i F − z O P i F y O P i F ( x O P i F ) 2 + ( y O P i F ) 2 ] [ w x P i F w y P i F w z P i F ] + m t o t a l ⋅ R ⃗ ~ O G F ⋅ V ⃗ O F = [ I ^ J ^ K ^ ] T [ ∑ i N m P i ⋅ [ ( y O P i F ) 2 + ( z O P i F ) 2 ] − ∑ i N m P i ⋅ x O P i F y O P i F − ∑ i N m P i ⋅ ( x O P i F z O P i F ) − ∑ i N m P i ⋅ ( y O P i F x O P i F ) ∑ i N m P i ⋅ [ ( x O P i F ) 2 + ( z O P i F ) 2 ] − ∑ i N m P i ⋅ ( y O P i F z O P i F ) − ∑ i N m P i ⋅ ( z O P i F x O P i F ) − ∑ i N m P i ⋅ ( z O P i F y O P i F ) ∑ i N m P i ⋅ [ ( x O P i F ) 2 + ( y O P i F ) 2 ] ] [ w x P i F w y P i F w z P i F ] + m t o t a l ⋅ R ⃗ ~ O G F ⋅ V ⃗ O F = [ I ^ J ^ K ^ ] T [ I x x I x y I x z I y x I y y I y z I z x I z y I z z ] [ w x P i F w y P i F w z P i F ] = [ I ^ J ^ K ^ ] T [ I x x w x P i F + I x y w y P i F + I x z w z P i F I y x w x P i F + I y y w y P i F + I y z w z P i F I z x w x P i F + I z y w y P i F + I z z w z P i F ] + m t o t a l ⋅ R ⃗ ~ O G F ⋅ V ⃗ O F = [ I ^ J ^ K ^ ] T [ H x H y H z ] + m t o t a l ⋅ R ⃗ ~ O G F ⋅ V ⃗ O F \begin{aligned} \vec{H}_{\Sigma _{\mathrm{M}}/\mathrm{O}}^{F}&=\sum_i^N{\vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F}\times \vec{P}_{\mathrm{P}_{\mathrm{i}}}^{F}}=\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F}\times \left( \vec{V}_{\mathrm{O}}^{F}+\vec{\omega}^F\times \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}=\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \tilde{\vec{R}}_{\mathrm{OP}_{\mathrm{i}}}^{F}\cdot \left( \tilde{\vec{\omega}}^F\cdot \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}+\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \tilde{\vec{R}}_{\mathrm{OP}_{\mathrm{i}}}^{F}\cdot \vec{V}_{\mathrm{O}}^{F}}\\ &=\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left[ \begin{matrix} 0& -z_{\mathrm{OP}_{\mathrm{i}}}^{F}& y_{\mathrm{OP}_{\mathrm{i}}}^{F}\\ z_{\mathrm{OP}_{\mathrm{i}}}^{F}& 0& -x_{\mathrm{OP}_{\mathrm{i}}}^{F}\\ -y_{\mathrm{OP}_{\mathrm{i}}}^{F}& x_{\mathrm{OP}_{\mathrm{i}}}^{F}& 0\\ \end{matrix} \right] \cdot \left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left( \left[ \begin{matrix} 0& -w_{\mathrm{z}_{\mathrm{Pi}}}^{F}& w_{\mathrm{y}_{\mathrm{Pi}}}^{F}\\ w_{\mathrm{z}_{\mathrm{Pi}}}^{F}& 0& -w_{\mathrm{x}_{\mathrm{Pi}}}^{F}\\ -w_{\mathrm{y}_{\mathrm{Pi}}}^{F}& w_{\mathrm{x}_{\mathrm{Pi}}}^{F}& 0\\ \end{matrix} \right] \cdot \left[ \begin{array}{c} x_{\mathrm{OP}_{\mathrm{i}}}^{F}\\ y_{\mathrm{OP}_{\mathrm{i}}}^{F}\\ z_{\mathrm{OP}_{\mathrm{i}}}^{F}\\ \end{array} \right] \right) +m_{\mathrm{total}}\cdot \tilde{\vec{R}}_{\mathrm{OG}}^{F}\cdot \vec{V}_{\mathrm{O}}^{F}}\\ &=\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left[ \begin{array}{c} \left[ \left( y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2 \right] w_{\mathrm{x}_{\mathrm{Pi}}}^{F}-\left( x_{\mathrm{OP}_{\mathrm{i}}}^{F}y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) w_{\mathrm{y}_{\mathrm{Pi}}}^{F}-\left( x_{\mathrm{OP}_{\mathrm{i}}}^{F}z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ -\left( y_{\mathrm{OP}_{\mathrm{i}}}^{F}x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) w_{\mathrm{x}_{\mathrm{Pi}}}^{F}+\left[ \left( x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2 \right] w_{\mathrm{y}_{\mathrm{Pi}}}^{F}-\left( y_{\mathrm{OP}_{\mathrm{i}}}^{F}z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ -\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F}x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) w_{\mathrm{x}_{\mathrm{Pi}}}^{F}-\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F}y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) w_{\mathrm{y}_{\mathrm{Pi}}}^{F}+\left[ \left( x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2 \right] w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ \end{array} \right] +m_{\mathrm{total}}\cdot \tilde{\vec{R}}_{\mathrm{OG}}^{F}\cdot \vec{V}_{\mathrm{O}}^{F}}\\ &=\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left[ \begin{matrix} \left( y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2& -x_{\mathrm{OP}_{\mathrm{i}}}^{F}y_{\mathrm{OP}_{\mathrm{i}}}^{F}& -x_{\mathrm{OP}_{\mathrm{i}}}^{F}z_{\mathrm{OP}_{\mathrm{i}}}^{F}\\ -y_{\mathrm{OP}_{\mathrm{i}}}^{F}x_{\mathrm{OP}_{\mathrm{i}}}^{F}& \left( x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2& -y_{\mathrm{OP}_{\mathrm{i}}}^{F}z_{\mathrm{OP}_{\mathrm{i}}}^{F}\\ -z_{\mathrm{OP}_{\mathrm{i}}}^{F}x_{\mathrm{OP}_{\mathrm{i}}}^{F}& -z_{\mathrm{OP}_{\mathrm{i}}}^{F}y_{\mathrm{OP}_{\mathrm{i}}}^{F}& \left( x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2\\ \end{matrix} \right] \left[ \begin{array}{c} w_{\mathrm{x}_{\mathrm{Pi}}}^{F}\\ w_{\mathrm{y}_{\mathrm{Pi}}}^{F}\\ w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ \end{array} \right] +m_{\mathrm{total}}\cdot \tilde{\vec{R}}_{\mathrm{OG}}^{F}\cdot \vec{V}_{\mathrm{O}}^{F}}\\ &=\left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left[ \begin{matrix} \sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left[ \left( y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2 \right]}& -\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot x_{\mathrm{OP}_{\mathrm{i}}}^{F}y_{\mathrm{OP}_{\mathrm{i}}}^{F}}& -\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left( x_{\mathrm{OP}_{\mathrm{i}}}^{F}z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}\\ -\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left( y_{\mathrm{OP}_{\mathrm{i}}}^{F}x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}& \sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left[ \left( x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2 \right]}& -\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left( y_{\mathrm{OP}_{\mathrm{i}}}^{F}z_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}\\ -\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left( z_{\mathrm{OP}_{\mathrm{i}}}^{F}x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}& -\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left( z_{\mathrm{OP}_{\mathrm{i}}}^{F}y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}& \sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left[ \left( x_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2+\left( y_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) ^2 \right]}\\ \end{matrix} \right] \left[ \begin{array}{c} w_{\mathrm{x}_{\mathrm{Pi}}}^{F}\\ w_{\mathrm{y}_{\mathrm{Pi}}}^{F}\\ w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ \end{array} \right] +m_{\mathrm{total}}\cdot \tilde{\vec{R}}_{\mathrm{OG}}^{F}\cdot \vec{V}_{\mathrm{O}}^{F}\,\,\\ &=\left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left[ \begin{matrix} I_{\mathrm{xx}}& I_{\mathrm{xy}}& I_{\mathrm{xz}}\\ I_{\mathrm{yx}}& I_{\mathrm{yy}}& I_{\mathrm{yz}}\\ I_{\mathrm{zx}}& I_{\mathrm{zy}}& I_{\mathrm{zz}}\\ \end{matrix} \right] \left[ \begin{array}{c} w_{\mathrm{x}_{\mathrm{Pi}}}^{F}\\ w_{\mathrm{y}_{\mathrm{Pi}}}^{F}\\ w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ \end{array} \right] =\left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left[ \begin{array}{c} I_{\mathrm{xx}}w_{\mathrm{x}_{\mathrm{Pi}}}^{F}+I_{\mathrm{xy}}w_{\mathrm{y}_{\mathrm{Pi}}}^{F}+I_{\mathrm{xz}}w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ I_{\mathrm{yx}}w_{\mathrm{x}_{\mathrm{Pi}}}^{F}+I_{\mathrm{yy}}w_{\mathrm{y}_{\mathrm{Pi}}}^{F}+I_{\mathrm{yz}}w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ I_{\mathrm{zx}}w_{\mathrm{x}_{\mathrm{Pi}}}^{F}+I_{\mathrm{zy}}w_{\mathrm{y}_{\mathrm{Pi}}}^{F}+I_{\mathrm{zz}}w_{\mathrm{z}_{\mathrm{Pi}}}^{F}\\ \end{array} \right] +m_{\mathrm{total}}\cdot \tilde{\vec{R}}_{\mathrm{OG}}^{F}\cdot \vec{V}_{\mathrm{O}}^{F}\\ &=\left[ \begin{array}{c} \hat{I}\\ \hat{J}\\ \hat{K}\\ \end{array} \right] ^{\mathrm{T}}\left[ \begin{array}{c} H_{\mathrm{x}}\\ H_{\mathrm{y}}\\ H_{\mathrm{z}}\\ \end{array} \right] +m_{\mathrm{total}}\cdot \tilde{\vec{R}}_{\mathrm{OG}}^{F}\cdot \vec{V}_{\mathrm{O}}^{F}\\ \end{aligned} H ΣM/OF=i∑NR OPiF×P PiF=i∑NmPi⋅R OPiF×(V OF+ω F×R OPiF)=i∑NmPi⋅R ~OPiF⋅(ω ~F⋅R OPiF)+i∑NmPi⋅R ~OPiF⋅V OF=i∑NmPi⋅ I^J^K^ T 0zOPiF−yOPiF−zOPiF0xOPiFyOPiF−xOPiF0 ⋅ I^J^K^ T 0wzPiF−wyPiF−wzPiF0wxPiFwyPiF−wxPiF0 ⋅ xOPiFyOPiFzOPiF +mtotal⋅R ~OGF⋅V OF=i∑NmPi⋅ I^J^K^ T [(yOPiF)2+(zOPiF)2]wxPiF−(xOPiFyOPiF)wyPiF−(xOPiFzOPiF)wzPiF−(yOPiFxOPiF)wxPiF+[(xOPiF)2+(zOPiF)2]wyPiF−(yOPiFzOPiF)wzPiF−(zOPiFxOPiF)wxPiF−(zOPiFyOPiF)wyPiF+[(xOPiF)2+(yOPiF)2]wzPiF +mtotal⋅R ~OGF⋅V OF=i∑NmPi⋅ I^J^K^ T (yOPiF)2+(zOPiF)2−yOPiFxOPiF−zOPiFxOPiF−xOPiFyOPiF(xOPiF)2+(zOPiF)2−zOPiFyOPiF−xOPiFzOPiF−yOPiFzOPiF(xOPiF)2+(yOPiF)2 wxPiFwyPiFwzPiF +mtotal⋅R ~OGF⋅V OF= I^J^K^ T ∑iNmPi⋅[(yOPiF)2+(zOPiF)2]−∑iNmPi⋅(yOPiFxOPiF)−∑iNmPi⋅(zOPiFxOPiF)−∑iNmPi⋅xOPiFyOPiF∑iNmPi⋅[(xOPiF)2+(zOPiF)2]−∑iNmPi⋅(zOPiFyOPiF)−∑iNmPi⋅(xOPiFzOPiF)−∑iNmPi⋅(yOPiFzOPiF)∑iNmPi⋅[(xOPiF)2+(yOPiF)2] wxPiFwyPiFwzPiF +mtotal⋅R ~OGF⋅V OF= I^J^K^ T IxxIyxIzxIxyIyyIzyIxzIyzIzz wxPiFwyPiFwzPiF = I^J^K^ T IxxwxPiF+IxywyPiF+IxzwzPiFIyxwxPiF+IyywyPiF+IyzwzPiFIzxwxPiF+IzywyPiF+IzzwzPiF +mtotal⋅R ~OGF⋅V OF= I^J^K^ T HxHyHz +mtotal⋅R ~OGF⋅V OF
上式的实际推导过程,是进行两次转置变化,在实际过程中可以理解成,适用于矩阵与矢量相乘的张量Tensor
乘法,因此也可将惯性矩阵 [ I ] \left[ I \right] [I]称为惯性张量Inertia Tensor
。而采用基于拉格朗日恒等式证明的三个向量的双重矢积公式,可能更利于理解:(为方便运算,忽略点 O O O的运动)
- 三个向量的双重矢积公式: ( r ⃗ 1 × r ⃗ 2 ) × r ⃗ 3 = ( r ⃗ 1 ⋅ r ⃗ 3 ) r ⃗ 2 − ( r ⃗ 2 ⋅ r ⃗ 3 ) r ⃗ 1 \left( \vec{r}_1\times \vec{r}_2 \right) \times \vec{r}_3=\left( \vec{r}_1\cdot \vec{r}_3 \right) \vec{r}_2-\left( \vec{r}_2\cdot \vec{r}_3 \right) \vec{r}_1 (r 1×r 2)×r 3=(r 1⋅r 3)r 2−(r 2⋅r 3)r 1
H ⃗ Σ M / O F = ∑ i N R ⃗ O P i F × P ⃗ P i F = ∑ i N m P i ⋅ R ⃗ O P i F × ( ω ⃗ F × R ⃗ O P i F ) = ∑ i N m P i ⋅ [ ( R ⃗ O P i F ⋅ R ⃗ O P i F ) ω ⃗ F − ( ω ⃗ F ⋅ R ⃗ O P i F ) R ⃗ O P i F ] \vec{H}_{\Sigma _{\mathrm{M}}/\mathrm{O}}^{F}=\sum_i^N{\vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F}\times \vec{P}_{\mathrm{P}_{\mathrm{i}}}^{F}}=\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F}\times \left( \vec{\omega}^F\times \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F} \right)}=\sum_i^N{m_{\mathrm{P}_{\mathrm{i}}}\cdot \left[ \left( \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F}\cdot \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) \vec{\omega}^F-\left( \vec{\omega}^F\cdot \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F} \right) \vec{R}_{\mathrm{OP}_{\mathrm{i}}}^{F} \right]} H ΣM/OF=i∑NR OPiF×P PiF=i∑NmPi⋅R OPiF×(ω F×R OPiF)=i∑NmPi⋅[(R OPiF⋅R OPiF)ω F−(ω F⋅R OPiF)R OPiF]